Dash Cluster light fault

[waheke27]

Any advice as to what is causing my 1987 Alfa 75 2.5 manual dash lights to go out when I turn on the ignition.

They turn on with the stalk light switch but go out when I try to start the car.

Has me baffled.

[colcol]

Sounds like a problem common to Alfa Romeo models 33, 75 and 90, undersize contacts on the ignition switch causes all this palava, i had the same problem with my 33, but noticed a slight burning smell in the car, too much current running through ignition, solution could be to get a new ignition switch, common problem with Alfa's, new ones available on Ebay, Colin.

[waheke27]

Thanks Colin.

I was still sceptical after your advice so after a lot of study of wiring diagrams and thinking, I worked my way back to the ignition switch.

Being stingy, I worked out how to pull it apart and cleaned up the terminals and the tiny springs and ball bearing.

Amazingly I got it back togather again and it worked! For a few starts anyway, but not for the cluster lights.

Except the lights came on when it was on full start position which was an improvement.

This improvement has convinced me it is the ignition switch which fortunately has now failed completely, post surgery.

A new one is on its way.

The only drawback is the doors will no longer be keyed alike.

Again, Thanks for your help Colin.

David

[shiny_car]

Are you able to open up the barrel and transfer the sliders from the original to the new barrel? Then you can keep the original key. I've done this with door locks, but ignition barrels may be tamper-proof, dunno.

Might be the opportune time to add a relay to, to supply power to the dash lights.

[colcol]

Before you install the ignition switch, take it to a locksmith and they might be able to change the tumblers in the ignition switch to the same as the door, big job changing ignition switch, retaining bolt has to be drilled out, the ignition switch i purchased from an Alfa Dealer about 25 years ago came with new door locks, so all the locks were the same, Colin.

[waheke27]

Thanks Guys for your help.

However, the minor inconvenience of having two keys is not sufficient incentive for me to enter the barrel of the new Ignition lock.

I will live with two keys.

As for the retaining bolt, after reading up on this, I dreaded the task of getting this out and adopted the idea of using a Dremmel to cut a slot in it, so as to get a screw driver to remove it.

Fortunately, the action of the dremmel vibration loosened the screw and I was able to remove it easily.

I have had a few occassions where fortune has smiled on me with this car which is a pleasant change from the sods law that has applied on most previous projects.

Is this an Alfa thing?

I hope it is and my good fortune with this car continues indefinitely.

[colcol]

My ignition lock bolt i reckon was locktited in, i tried a hacksawing a slot, but it didn't work, if i was to do it again i would use just a normal bolt, not a shear bolt, as with these old Alfa's, the days of them being worth something and getting stolen, is long gone, make sure you run things through relays and not your new ignition switch, Colin.

[waheke27]

Colin

I will also be using a normal bolt for just that reason.

I'm not sure how to start with inserting a relay into the circuit though.

I understand that they switch full battery at the relay to save high current transiting the ignition contacts but I don't know where would I get the appropriate one and if they come with instructions.

Any further advice. Sorry to be a pain.

[colcol]

See what runs off your ignition switch and if its high drain, put it through a relay, a particular high user of volts on my car was the after market aircon, i could actually smell the switch burning when i switched on the aircon, all the modern Alfa's use relays on big amperage components, Colin.

[waheke27]

So I have installed the brand new ignition switch and it works fine but the dash lights still don't

Any further advice.

Also where can I find the in cabin earths.

Help!

[colcol]

When you say 'dash lights', do you mean illumination, ie lights to see the speedo or oil, charge, temp lights?, if it is speedo lights not working, check the earth, if thats ok, then check the illumination rheostat switch, they are known to fail, if all the warning lights are not working, check the earths and power going into the instrument binnacle, Colin.

[waheke27]

Thanks Colin

The problem concerns the illumination of the gauges; not the gauges themselves.

When I turn on the park /headlights using the stalk switch, the lights come on and are adjustable by the rheostat as required.

When I go to start the car, the lights extinguish and don't relight when the car is running.

Iy can only be that the power or the earth is disconnected when I rurn the key, but I cannot determine where this happens from the circuit diagram.

I have "serviced"  the key operated supply relay (I35) by cleaning the points inside it and I can hear it operating correctly when I turn the ignition key.

I still haven't found the in car earths.

In the absence of any further advice, I will need to consult an Alfa Savy Auto elec. Any recommendations?

Regards and thanks