Project car - 1989 75 3.0 V6 [Updated 12 November 2021]

[MD]

shiny,

Got a question for you. When I took my evap. unit apart for servicing, the control knob for the "open"/"closed" air selection was not wired up but a whole bunch of wires were lose. I have tracked down the motor connections and all the wiring to the little black box with the blue relays in it. However I need the wire colour code for the control switch connections and the pin numbers that they connect to. Can you help?

[jazig.k]

My rear window heater works now, burnt out connector just like yours actually! It only gets 10v at the window though so still have some supply issue. Might be a common problem?

[shiny_car]

When I took my evap. unit apart for servicing, the control knob for the "open"/"closed" air selection was not wired up but a whole bunch of wires were lose. I have tracked down the motor connections and all the wiring to the little black box with the blue relays in it. However I need the wire colour code for the control switch connections and the pin numbers that they connect to. Can you help?

This is how the recirc knob is wired in my car:

C: NC
L: (single) pink
M: white with black dashes
H: NC
B: (double) black (with right-angle spade terminal)

This is how the fan speed knob is wired in my car:

C: (double) pink
L: yellow
M: purple
H: grey
B: yellow with black stripe

(double: two wires connected to the single terminal)

My rear window heater works now, burnt out connector just like yours actually! It only gets 10v at the window though so still have some supply issue. Might be a common problem?

Could be. 10V doesn't seem right at all.

[MD]

jazig

The demister is a high current using device and if you have measured this voltage while it was in actual use, the voltage may be reasonably close to being normal. Especially if the alternator was not running well above idle at the time of measurement.
If your battery is anywhere near marginal (and located in the engine bay) especially in cold temps this time of the year, I would say just live with it.

shiny.

Thanks for the info. Sending a PM.

[VeeSix]

Another fantastic update thankyou Richard

Re red line fading, yes Richard, all the 75s I have had come thru were of similar appearance except for the occasional one with tinted windows, not so bad, I think your careful masking and respraying method should work well

What are you going to do pedal cover wise Richard, stick with rubber or go metal?

I am not sure if you know or not but the 75 originally came with nice rubber covers that had the Alfa Romeo emblem as a centerpiece

You appear to have got off lightly re the inlet rust, the 90 and 75 suffer badly from this area, I have seen complete sections basically gone, I am currently stripping a 75 3.0 the same as yours and it's double your lotto win

Fantastic job with the vents, yes maybe just short of the 75 originals flow but a hell load more robust

Re your moving the battery location, repairing rear demister line and adding a relay, in speaking with you previously you had mentioned you had not had much to do with the 164, out of interest Richard the 164 has the battery mounted on the left side in the boot and just ahead of it a relay with fuse for the rear window demister, I will attach a photo 

[VeeSix]

The 164 gets a lot of the same type melting around the fuse location similar to your connection find 

[VeeSix]

Attached is a photo Richard out of interest of the clock with all the extra features from the 90 and 75 series 1, notice the extra buttons, off memory actually the 33 series 1 gold clover leaf had the system as well and possibly the Alfetta 2.0 gold clover leaf, just above the clock is a probe looking piece of plastic with wire and connection, this is the temperature sensor and was located on the 90 and 75 just behind the right side headlight, basically slid into a hole which went into the front of the wheel well area and took the reading from there, bet if you checked your 75 the probe support hole would be there 

[shiny_car]

Another fantastic update thank you Richard

Thanks David.

Re red line fading, yes Richard, all the 75s I have had come thru were of similar appearance except for the occasional one with tinted windows, not so bad, I think your careful masking and respraying method should work well

What are you going to do pedal cover wise Richard, stick with rubber or go metal?

I think repainting the 'red line' should work ok.

I have a set of new pedal-pads to fit. They are Zender copies (I first saw Zender ones as aftermarket parts for the 156), which are metal, with horizontal rubber inserts. I had them on my 156, currently on the 155, and bought a set off eBay for the 75. I prefer the metal-look; more sporty.

You appear to have got off lightly re the inlet rust, the 90 and 75 suffer badly from this area, I have seen complete sections basically gone, I am currently stripping a 75 3.0 the same as yours and it's double your lotto win

Yeah, the rust isn't too bad. I already patched it from the other side, but I have seen photos of cars from the UK, where people are forced to cut out the whole section and rebuild! Fortunately, Australian cars have generally held up well because of the environment.

Fantastic job with the vents, yes maybe just short of the 75 originals flow but a hell load more robust

Cheers, they turned out well. Thanks again for providing them. 

Re your moving the battery location, repairing rear demister line and adding a relay, in speaking with you previously you had mentioned you had not had much to do with the 164, out of interest Richard the 164 has the battery mounted on the left side in the boot and just ahead of it a relay with fuse for the rear window demister, I will attach a photo 

OK, interesting. Having a relay definitely seems a good idea, to avoid the long length of high-current wiring. Ditto the headlights and starter solenoid. All benefit from upgrades for both functionally/reliability and safety.

just above the clock is a probe looking piece of plastic with wire and connection, this is the temperature sensor and was located on the 90 and 75 just behind the right side headlight

Cool. Do you have a pic of the fuel flow sensor, and where is that fitted?

[GTVeloce]

My rear demister worked, but only just. To improve the voltage at the glass, I installed a relay in the boot covering (GTV) where the fuel vapour separator lives. Feeding this was easy as my battery is already in the boot. Once I hooked it up, full voltage at the window!

However, the existing relay in the fuse box under the dash chatters terribly when I switch it on. It sounds like it is constantly switching itself on and off. I just used a simple four pole relay with terminal 30 coming from the battery; 85 just earthing to the body close by; 86 coming from the black wire that normally feeds the window and then 87 going to the window.

Any thoughts why it would do this and how I might rectify it?

[shiny_car]

@ GTVeloce: that's how I intend to wire my demister, but I don't know why your dash relay is chattering. What I'm unclear about is whether the dash relays are a simple SPST (single pole, single throw) relay like the new boot one; I suspect not. Or whether the dash relay has an inbuilt timer or some sort of sensor to determine when the demister is hot. The new additional relay may be causing havoc with the dash relay. However, you could try a replacement, in case it is faulty.

Not as many photos this past month, but most of the work entailed wiring the alarm system. There were over a dozen connections to be made, which meant referring to wiring diagrams to help locate the relevant wires, plenty of soldering and heat shrink, and creating a 'neat' and reliable installation. Can alarm wiring ever be neat?!

However, first I re-installed the HVAC unit. The air inlet rust was cleaned with a wire brush, then coated with Cold Gal paint. The area was made smoother using bog.







I cut a basic paper template, then two pieces of fibreglass matting. Polyester resin, thickened with Q-Cel thickener, soaked the matting into position. In the cold weather, I used a heat gun to speed up curing, though managed to singe a few strands of matting.  Finished with a coat of Alfa Rosso 130 paint. This area is not visible from the engine bay, so the result did not need to be perfect.







I eventually replaced the original foam around the inlet vent with new closed-cell foam. The HVAC unit was bolted back into position but I've lost that photo! So I'll show you next month.





Moving across to the right side of the dash area; the steering column is adjustable for tilt and reach (tilt-slide). The whole area was oily, which attracted dust and dirt. I suspect some indiscriminate spraying with an oil aerosol created the mess.







Wax & Grease Remover was used to wipe the area clean. I detached the clutch master cylinder from the pedal, cleaned, and re-greased, plus new stainless steel split pin.









The brake light switch sat above and to the right of the steering column. Whilst it was very firmly in position, the locking nut was not tightened. The wire for the rear central brake light was 'secured' using a Scotch-lock clip (these can be unreliable).

I tidied the area by removing the wire attachment (will relocate via a relay in the boot), with heatshrink over the exposed wire, and tightened the locking nut.





In the top right corner behind the dash sat this array of wiring looms and plugs, and a major ground wire attachment point (labelled G52 in wiring diagrams). The plugs simply unclipped apart, and the back sections unclipped from the metal support bracket. The support bracket was secured by two bolts.







The ground wires attached to the metal terminal bracket, which in turn was bolted to the dash. As such, the only electrical connection to the chassis was through the bolt. But appeared to be little 'bare metal' contact; the paint was still in place, with the connection relying on the bolt threads, although even the thread inside the nut appeared painted. So not a very good connection (though still obviously worked), and one that I decided to upgrade.



I used a length of 4ga wire, hex-crimped with lugs on each end. An unused 6mm hole was located nearby in the kick panel area. I used the Dremel to remove the paint back to bare metal, and threaded a bolt into position. Then secured the 4ga wire.







The 4ga wire was secured to the original 'G52' ground point terminal bracket, and plugs refitted. I found an additional set of plugs hanging loosely below, carrying the wires to the front right (driver's) door, which I clipped into the proper position.



This was the central locking control unit, and associated wires for integration with the alarm's remote locking feature. The design uses the common setup of a 'negative trigger' to activate the unit: when any of the sensor wires (two from each front door lock) detects a 'ground', the control unit activates the central locking motors in all other doors to follow suit. For example, if you manually unlock the driver's door, the 'unlock wire' in the door is grounded; when the control unit detects this, it unlocks all the other doors too. Likewise, when manually locking the door, the 'lock wire' in the door is grounded, and the control unit locks all the other doors.

Remote central locking works by connecting to a pair of 'door lock' and 'door unlock' wires, any door. The remote unit pulses a 'negative signal' to the wire (ie: temporarily grounds the wire via a relay), causing the factory central locking unit to lock/unlock all doors accordingly. Remote central locking alarms can be configured to suit any car, whether they require a negative trigger or positive (+12V) trigger, or something else.

The sensing wires in the car were:
front right door: brown (unlock) + purple (lock)
front left door: brown/white stripe (unlock) + purple/white stripe (lock)

It was evident a remote central locking device was previously fitted into the car. Remnants of wires were attached to the brown and purple wires in the kick panel area on the driver side.





Power for the alarm, siren back-up battery charging, and upgraded supply to the CD headunit was created via a spare 9.5mm blade terminal on the back of the fuse board. All three fused wires were combined and crimped to a single 9.5mm terminal, insulated with heatshrink.



One ground wire for the alarm (there are two because alarms provide a back-up wire in the event one fails), and ground wire for the headunit, were fastened to the new ground point via ring terminals. The area was then protected against corrosion with grease.



3-point immobilisation was a feature of the alarm, so I chose three suitable critical wiring paths to tap into: starter, fuel combo-relay trigger wire (relay to activate fuel injectors and fuel pump), and fuel pump powerwire. The principle of immobilisation is diverting these wires through the alarm, where relays open/close the circuit. With the alarm activated, these circuits are 'cut' and the car cannot be started. Alternative choices would be wiring for the ECU, injector control unit, ignition coil, and igniter.

All three wires were amongst the plugs behind the dash. Rather than cut each wire, I separated them from their plugs, then connected each end to the alarm. The immobiliser wires and relays are rated to 25A; instead of thick wire to meet this rating, the alarm uses two thinner black wires per connection, which you may notice in the photo (ie: two thinner wires, each capable of handling at least 12.5A).



And after completion of the main alarm wiring, everything was relatively neat and tidy.



Over the next month, I will endeavour to complete the wiring behind the dash. See you then.

[ARQ164 Shane]

Hi shiny,
I like my spaghetti with sauce lol .
I take my hat off to you I'm not is brave as you to take out the dash .
but I will have to, to take my dash and spray it black with VHT vinyl paint .

cheers mate keep up the good work, Shane

[MD]

Shiny,

Just finished the rebuild of the air conditioner on the family 75. Got it working a treat but I had to get a bit tricky to do it. When eventually you get around to rebuilding yours, here's few tips for you.

1 The thermostat location on the outflow side to the evaporator is wrongly placed and causes a long delay in the compressor cycles. To fix this you need a new thermostat ( mine cost less than $20) with a 500mm capillary and the tube should be inserted directly into the evaporator core.

2  The thermostat itself is often a sloppy tolerance and it needs to be "reset" to cycle the compressor on and off in a much shorter duration than they often are- say 3* above set point. The one in mine went +12* before kicking in and by this time the cabin temp went too high.

3 Recalibrating the thermostat is not that hard and is it done in two stages (a) the bellows return is restricted so it doesn't go back further than 10*. This gives it faster cycling duration.(b) the internal switch that activates the compressor requires adjustment by the available screw which is usually sealed at the factory. To do this, rig up a light to act as the compressor. Power up the switch contacts. Continue to screw the adjuster until the light comes on. Back it off a quarter turn. What this will do is dramatically shorten the time the bellows take to make the switch contact.

If all else is good, this modification is the cherry on the cake that ensures a stable temperature in the cabin without ridiculous rise and fall swings.

Cheers.

[shiny_car]

cheers mate keep up the good work, Shane

Cheers mate!

Just finished the rebuild of the air conditioner on the family 75. Got it working a treat but I had to get a bit tricky to do it. When eventually you get around to rebuilding yours, here's few tips for you.

Thanks MD, I appreciate that! You've certainly sorted yours out nicely; I don't have such a good understanding of the intricacies of an AC system, but that all makes sense, so I'll look into it once the car is back up and running.



This month's progress was hampered by several events, including sale of our 159SW, and purchase of a *cough* Blue Oval car, and some minor man-flu, but also bad sleep from a crying kid with baby-flu  .

Firstly, a few photos that would have fitted with last month's update. This is the HVAC unit fitted back into position.



And these show the wiring on the right side of the dash, helping put into perspective the position of plugs and looms shown in photos during the alarm installation.





Onto a modification, this is a powered right side door mirror, and matching blanking triangular trim piece (I had already dismantled the mirror to inspect, hence the blue masking tape over the glass). They are from LHD cars (mirror from Europe off eBay; trim piece from US alfabb.com forum member). 75's have only one power mirror, on the 'passenger door'; hence, RHD Australian cars have a left power mirror and manual right mirror. Opposite in LHD cars. This modification fits my car with two power mirrors.



The power mirror will replace the manual mirror, and triangular trim.





The door trim and sound deadening 'padding' were removed to access the door wiring. I will be refurbishing the doors (windows, exterior handles, etc) in detail in the future, and will revisit dismantling pieces at that time.





The existing door speakers and wiring will be replaced, so the redundant speaker wires and plugs were removed. The wires pass out through the rubber 'tube' inside the door, across the door jam, and into the cabin.





After cutting the plugs, the wires were pulled back. It was easy enough to identify the wires in the loom in the cabin; also needed to unwrap electrical tape that bunched the wires together. Also used the two speaker wires to 'pull through' new wiring. The power mirror operates from three wires. Two new wires (yellow + blue) were taped to the end of one speaker wire, and pull back into the cabin.







To the second speaker wire, I attached the third new power mirror wire and some stiff figure-8 (purple) speaker wire. After pulling the new wires as far as the door jam, the tape was unwrapped. The stiff figure-8 wire was left in this position to help feed new speaker wire.





The original grey/black speaker wire was then rejoined to the blue wire and pulled completely through into the cabin. Followed by new figure-8 (matte grey) Stinger HPM Series 16 gauge speaker wire fed from the cabin into the door jam, then taped to the purple speaker wire, and pulled into the door. The second blue wire was marked with a 'black stripe' using a marker pen to distinguish it from the other blue wire.







I checked the left door to see how the wiring was installed. My new right mirror had the plugs, so I needed matching plugs to connect with the new wiring.



Rather than fit a new aftermarket plug (would have been easy enough though), I determined the speaker plugs were the same. The old speakers and plugs were being removed anyway, so I had the opportunity to attach them to my new power mirror wiring. Note the door speakers were not original, but aftermarket VDO 2-way coaxial 4x6".





Test-fitting the speaker plugs with the power mirror plugs.



After consulting the wiring diagram in the workshop manual, I soldered the corresponding wires in the plugs with the new power mirror wiring. Of course only three wires in use, with one removed from the plugs.



The three new power mirror wires were then neatly threaded through the car, following the loom to the meet with the existing wires for the left power mirror.



Where the loom passes under the floor carpet, there is a connecting plug. The yellow wire is a shared ground/negative wire for all mirror motors (two motors in each mirror). Here was a good place for the wire to branch to the left and right mirrors, and therefore join the new yellow wire to the existing. I also misread the wiring diagram because it is written for LHD cars: notice the existing two wires to my left mirror are 'blue + blue/black'. Rather than install another set of 'blue + blue/black' wires for the right mirror, I strictly should have fitted 'yellow/black + blue/yellow' wires. Of course, it doesn't matter.



I couldn't find terminals amongst my spares to fit the new blue wires into the black plug, so it was easier to use an aftermarket plug. I could also have run the wires in continuity, without a plug, but you never know if you have to disconnect the wiring looms at any stage, even if unlikely. The yellow wire was soldered to the existing.





The final wiring connections were for the blue wires into the control switch plug. I determined the terminals were the same as those in car radio ISO plugs. I had a spare plug, so cut two ends from the radio plug and soldered to the blue wires for the power mirror. The wiring diagram showed where to fit the right power mirror wires.







Here, the plug is fitted into the back of the mirror control switch and completes the modification! However, I am yet to test that it all works because the car has no battery fitted. I am confident it will work, but when I have time, I will 'bench test' using my external power supply.



Next job, attaching the main power feed to the fuse board. A while ago, you may recall I discarded the original power wires, which originated from the engine bay (battery > starter motor wire > extension to terminal board > 2x wires to fuse board). This was the old photo showing the original wires:



Now the car's electrical system will be supplied by a single 4ga power wire. Using the two original 9.5mm tab terminals remained the easiest option, so I carefully unravelled the groups of wiring strands into two smaller branches. New terminals were crimped to the wire (reinforced with solder), and insulated with heat shrink tubing.







The wire was connected and laid across the floor for connection to the distribution block on the passenger side. I need to wait until the dash is refitted to know exactly how long the wire will be, before cutting and connecting.





Final task for the month was installing new speaker wire through to the boot. Like the passenger side, two sets of figure-8 Stinger HPM Series 16ga wire; one for a new door speaker, the other for a new speaker mounted in the cabin. The two sets of wire were secured together with electrical tape, and passed alongside the existing wiring loom by the door sill.





Under the rear seat, the wiring passes through a couple holes in the metal brace. More plastic split conduit was fitted around the wires to reduce the risk of chaffing and short circuits. Notice one of the main ground wire connections under the seat (called G63a in the workshop manual); there is a similar one on the left (G63b). The fuel vapour return tube also runs along this area.



Here, the wiring runs over the rear wheel arch behind the rear seat, before entering the boot through a small hole. The seat belt was unbolted from the lower anchorage point for easier access.



That's it for the month! A few minor areas require tidying up, but I am close to refitting the carpet and reassembling the dash.

[GTVeloce]

Great work as always Shiny.

I'm puzzled; are you going to install an amp (or two) for your ICE? Your wiring suggests not unless it is going to be under the dash but given the great care and attention to detail you have done with the electrical system to date it would be such a shame not to have the system amplified.

If you are going to install it under the dash, where? Or do we just have to wait with baited breath till the next update? 

[shiny_car]

Thanks.

ICE (of the music kind!  ) is another hobby of mine. So yes, there will be a relatively simple system installed by my standards, and will include a 4-channel amp to run the front speakers 'actively' (8" door woofers + 3" wideband drivers (mid-tweeter)), and a second amp for a sub, all via an Alpine headunit and PXA-H800 digital processor. Nothing too bulky or heavy, but high quality installation and sound. Most gear will be boot mounted, including the amplifiers.