Acc Fuse blows 1991 formula - Third Generation F-Body Message Boards

oldmoparbuff · 08-12-2009, 11:30 PM

New to F-bodies and new to forum, lurking for a couple of weeks now.
This forum contains a huge amount of information.
It was this forum that allowed me and my son to purchase a 1991 Formula.
This car will be a much better starting point for my son first car because of the info here.

Car was in unknown codition when we purchased it.
I did get the engine running.

Todays issue is that the Acc 20 amp fuse blows.
I measured a dead short on the load side of the fuse terminal.
I pulled the covering off of the harness and the solid orange wire shows sign of getting hot-insulation damage. I have traced this wire as far as the column where my access is limited. I have disconnected all lamps in this circuit. I'm sure the orange wire needs to be replaced. my Haynes manual shows the following lamps are in this circuit: Map lights, Right and Left Courtesy lights, Glove box light, Right and Left dr jam switches and a light switch. I am assuming the light switch is part of the dash dimmer switch.

Any help would be appreciated.
Anything else on this circuit?
Best place to find junctions where this wire comes together in the harness?
A better schematic?
I hate to blindly cut the wire and sub another in.

Thanks All.

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Pocket · 08-13-2009, 07:43 PM

That harness is very difficult to remove and replace short of completely gutting the interior

It starts at the fuse block, moves up to the hush panel lights if equipped, then to the door jamb switches following the runner sleeve at the base of the windshield behind the dash(it must come out to remove this harness)
It then goes up the drivers A pillar to the rearview, then to the dome light, then to the 3rd brake light(included in this harness) and has a ground near the dome light

I can take pics if necessary

A JY harness would likely be better than attempting to troubleshoot your original

tony_cogliandro · 08-13-2009, 07:58 PM

pm me your email address and i will send you the factory wiring diagrams.

Pocket · 08-13-2009, 08:21 PM

http://www.austinthirdgen.org/mkport...me_hardtop.jpg

Why is everyone so particular about PMing or emailing pics/diagrams around? It makes it so much more difficult for the next person who attempts to remedy this problem

HCR13 · 08-13-2009, 08:33 PM

Most common issue to blow the Acc fuse is your cigarette lighter. Make sure there isn't a penny or anything else in there...or just unplug the lighter and see if it still blows. If not, check the overhead console (if so equipped) or the dome light, make sure the backing isn't touching the bare-roof metal and grounding it. If those don't fix the issue, then it could be a bad harness...

oldmoparbuff · 08-13-2009, 10:31 PM

thanks all.
I will work on it again in the morning.
My son left on a 50 mile backpack trip with our troop.
I hope I can have the interior all put back together and most electrical issues resolved.
main issues left.
- Mysteriously there is no fluid in the transmission.
- Found a drivers side fender same color as car - huge time saver.
- Trunk pull down not operational.
- Electrical issue.
- heater core.

I'm sure I will uncover a few more before we are driving.

oldmoparbuff · 08-14-2009, 02:34 AM

Good call.
I tore into the console to check the cigarette lighter.
I was rewarded with a view I would hate to experience.
Melted wire, scorched carpet, a good 8" of wire had no insulation left both leads that connect to the lighter where fused together.
This had to scare the blank out of somebody.

the stock wire seems too small to carry the rated current.

HCR13 · 08-14-2009, 02:43 AM

Quote:

Originally Posted by oldmoparbuff

Good call....

oldmoparbuff · 08-17-2009, 03:31 AM

Holy cow.
Took me all day today to get the dash out.
Now I have total access to the harness.
The melted insulation goes all the way to the butt splice.
Also shorted a couple of wires to the transmission selector switch.
Going to u-pull-it in the morning.

My son is out on a 56 mile backpack trip with the troop and I hope I can get everything put back together before he returns tuesday.

Honestly I wish I would have gone. Sleeping on the ground is a step up from laying on your back working with your head behind the dash.

thanks for the help.

HCR13 · 08-17-2009, 03:40 PM

thats true. But it should be easier to put back in than taking it out... I would take the seats out if you haven't already. It'll make things easier...

oldmoparbuff · 08-17-2009, 09:40 PM

Today was a good day.
Went to two different wrecking yards to get a harness and a duct to replace my cracked one.

Pulled two dashes apart getting good at it. First harness had the same problem mine did so I passed , but I did get a goog duct.

Second car yeilded both a good harness and also a perfect dash pad for $10.

I forgot how much fun it was to wonder around a wrecking yard.

HCR13 · 08-18-2009, 01:38 AM

Quote:

Originally Posted by oldmoparbuff

I forgot how much fun it was to wonder around a wrecking yard.

X2