Wiring question - 156 GTA (FIXED)

[poohbah]

This is actually a follow on from my previous issue with ASR Off not working, and am just looking for suggestions before I take it to an auto sparkie.

As previously indicated, I found a blown 10amp fuse (one of the "services" fuses) and once replaced, ASR and stereo resumed working properly. The Owners manual indicates the services circuit looks after ASR and stereo, among other things.

However, after about 6 weeks, the same fuse blew again, and since then it has been recurring. In fact, it seems to occur the instant I put it in reverse gear.

When the fuse blows, the ASR off switch stops functioning, and the stereo doesn't shut off automatically with the ignition, and if driving, the stereo will cut out after 20 mins (though it immediately works again if you switch it back on).

I've pretty much ruled out the stereo/stereo harness - I totally removed the head unit, replaced the fuse, and it was all working fine again until I put it into reverse.

Which makes me suspect it is to do with the wiring going to the ASR switch, which is immediately to the right and below the gear shift (ie it is exactly in line with the gear shift when you put it in reverse).

I've pulled out the gear shift surround multiple times to make sure the harness is not being pinched, I've disconnected the switches, visually checked the wires as best I can, but can't see anything obvious.

While it doesn't have any other effect on the car, or the way it drives, it is a pain in the backside.

I suspect the previous owner had the same problem and rather than finding the cause and fixing it, tried to work around it by sticking in a 20A fuse instead (when I replaced the original fuse I found a wrong amp one fuse had been inserted). That doesn't seem a very sensible approach to me. And it obviously didn't stop it from blowing anyway.

(And before you ask Bazz, yes I've been disconnecting the battery before touching anything, including the fuses. Once burnt , twice shy...)

[bazzbazz]

Take a look at the wiring going to the actual reversing switch on the gearbox and see if it's shorting out somewhere along the way.

Just a stab in the dark . . . .

[poohbah]

Cheers bazz, where do I find it, and how hard is it to get to?

[poohbah]

Have just discovered the reversing lights are not working, so you're clearly on the right track Bazz.

No warning lights on the dash though - so I've got no idea how long they've been defective.

Have had a couple of suggestions in addition to the reversing switch and associated wiring, but also to check the rear light clusters. Will have a look tomorrow in daylight.

[poohbah]

Update - Issue has been resolved.

As indicated before, I tracked it down to the reversing lights, though after dismantling both rear clusters couldn't see anything obvious myself and the fog lights in the cluster continued to work fine.

After faffing around for a couple of hours myself without luck, I arranged to take to the car round to an Alfa driving auto sparky who lives nearby.

After lengthy investigation he tracked it down to a short in the loom running from the rear of the body shell into the bootlid.

Pulling down the rubber sheath and peeling back the insulating tape over the wires in the body-to-bootlid loom revealed that the insulation was cracked on multiple wires in at least three spots where the loom had been folded back on itself by the regular opening and closing of the boot. Over time, the plastic had dried out and cracked.

All split sections have now been reinsulated and straightened out, and all is working fine again.

However, given the the insulation in general looks pretty crusty due to age, I now plan to buy a new standalone loom for the boot section, which seems to be a simple plug and play setup.

Because the car is black, and that wiring loom sits up against the inner side of the bootlid, it gets pretty hot if its been parked in the sun. So I reckon the insulation deteriorates much faster than normal. If the car has been sitting in the sun for any length of time the body gets literally too hot to touch, which was never the case with my white one.

[bazzbazz]

Wires shorting out . . . . .
Things getting excessively hot . . . . . .
Possibility of fire . . . . . . .
It's a 156 . . . . . .

I'm seeing a reoccurring theme here . . . . .   

[poohbah]

At least the potential ignition point is as far from the engine bay as possible this time.