Electrical issues help needed

[patrick1151]

agreed on the rear defogger but I now know thats not the source of the main issue. Which current speculation has as a short or a bare wire on my rear taillight wiring. I am just going to open the panels up and trace the wiring I guess.

[Len]

Hi Paddy.
Whish you were closer. So I could help .
I am going to undersatd that when you turn the ig key to the on position and not the start the fuse blows
??? is the headlight switch off bee sure.
Len
Does any one have a 77 astra wagon wiring diagram ?
Len

[patrick1151]

yes to both Len and no to the lights. I checked the solenoid wire first as I was doing some work under the hood in that area when this first flared up but there is nothing obvious under there.

[spencerforhire]

I'm trying to figure out how things from 2 different circuits can be on one fuse; the idle stop solenoid, gauges and idiot lights are on one circuit that's fed from the ignition switch during on and start. The actual tail lights(park lights) and instrument panel back lighting are from a different circuit that has power without the key. If you mean signal lights when you say taillights, that's a 3rd circuit.
I just spent the better part of an hour labeling all the wires in and out of a Vega fuse box; I sure hope it helps

[my79monza]

GM in many of their cars made the tilight harness seperat from the main harness from the fuse panel.
Quite often running the wiring down the drivers side to the rear.
check behinfd the left side tailight and see if there is indeed a plug in, unpluging it will tell if the issue is at the rear or somewhere between fuse panel and rear.
One place to investigate is the licence plate wire as it has to pass through the body panel.
Merle

[patrick1151]

Thank you so much that should help lots. What year Vega us this for? It doesnt look the same as my fuse box but hopefully the wires are the same so I can trace them. I am not sure which side is the top of the fuse box in your picture but the fuse that I keep blowing is my top middle fuse.

Thanks Merle for those hints as well

[spencerforhire]

Diagram is for a 77 Vega should be the same as your Astre; the top middle fuse is for gauges, idiot lights, idle stop solenoid and low coolant relay. Pretty well every 18ga. pink wire in the car is on this circuit.

[Len]

Shannon, Are you sure the fuse box pic Spence provided is wrong ?
Can you provide a pic or drawing or provide some sort of illustration .
Like this

Top
Gauges fuse Ignition fuse radio fuse Lighter fuse

ECT be as specific as poss it may help in finding the right wiring diagram .
In my experance if your fuse box is not the same then I think spence has provided the wrong pic . If this is the case the it all could be different and we could be walking down the wrong path
Len

[patrick1151]

I will probably Friday as last night was day 1 of my 3 in a row in Port Alberni which is 12 hou shifts+5.5 hours driving time. Thank you all

[patrick1151]

Ok I am starting to make some progress here, I bought some new fuses today and started changing some of the old fuses. The taillight fuse looked fine but when I put a new one in my taillights and dash lights started working. Thank goodness. I also came across a possible issue? On my firewall, there is a place where a fuseable link for the rwd bolts to and another wire is bolted there as well. The piece they bolt to is broken in half and probably not providing a proper ground. I dont know what that other wire is for but I will have to figure out. This piece is only on rwd equiped Vega's and Astre's from what I have seen.

[spencerforhire]

Lifted this out of another thread and it appears to be out of a GM service manual- looks to be the same as what I took off of the Mitchell Vintage Wiring CD.

[patrick1151]

that is thw same as my fuse box.

[marco_1978_spyder]

Thats the peice I was mentioning in my 1st reply. It's a breaker for the rwd.

[patrick1151]

right, now I just need to find a new one or hope my parts car has a good one.

[monzaaddict]

Unfortunately the Monza/Sunbird wiring diagram does not show a rear defrost, but it should not be on the tailight fuse anyway. The rear defrost circuit should have a timer relay in it somewhere that you could disconnect to isolate it from the rest of the wiring.

I haven't looked at this in a while but from what I remember because the defogger is an add on option the fuse is not in the fuse panel instead the power is drawn from the engine harness at the red wire from the alternator. On my 75 there was an inline fuse holder added at the factory and wrapped with harness tape. I believe there was also a circuit breaker on the firewall.

The relay is mounted on the left hand lower corner of the dashboard. You should be able to see the three screws as soon as you open the drivers door.

on my car when the defroster wires began fraying I just cut them back behind the headliner and added new wire and the correct terminal.