1990 C4 Blows CTSY fuse instantly

[DonB]

After a lengthy overhaul I finally got to drive my C4. We put the new seats in today. All was going great. Had a long lengthy drive today and was thrilled with the performance as well as everything was working again. Went to restart the car after dinner and noticed radio was on but NO sound as well as NO courtesy lights or LED in the A/C temp window. I found the CTSY fuse blown. I replaced it and it immediately pops. I realize it is a short to ground "somewhere." The car has never done this before.

Any one have any ideas or previous wiring issues they can share. I hate like hell to rip it all apart looking for demons. This is very frustrating. Thanks, Don

 

[Hib Halverson]

Do you have the factory service manual?

If so, take a look at the interior lighting wiring and troubleshoot for a short between the fuse and the lamps.

 

[DonB]

Do you have the factory service manual?

If so, take a look at the interior lighting wiring and troubleshoot for a short between the fuse and the lamps.

Hi Hib. Thanks for the input. I see you were previously involved with a similar problem a few years ago. I've located the CTSY diagram on page 8A-11-3 and I'm looking for splice S241. Where in the manual does it tell you where the splice is located? I've looked all over and can't seem to find the reference to it.

Thanks, Don

 

[Hib Halverson]

Look on pg 8A-114-4.
S241 is in the IP harness near the radio receiver.
Also, read the troubleshooting hints on 8A-114-5.

Good luck.

 

[DonB]

Look on pg 8A-114-4.
S241 is in the IP harness near the radio receiver.
Also, read the troubleshooting hints on 8A-114-5.

Good luck.

Yea thanks Hib. It says to check CKT 40 for open or short to ground. It is the orange HOT wire for all those accessories on that circuit. I kind of guessed that was the source of the problem as fast and as violently as the fuse blows. It has to be a total short to ground. Now to find where.

I'll keep you posted. Hopefully it's an obvious one. I'm figuring on removing all the various load circuits from it and re-connect them one at a time until I find the one that blows the fuse. Process of elimination. Then I can trace down that leg.

Later, Don

 

[DonB]

I thought I'd throw out an update. After practically totally dismantling the dash to find splice 241 I separated the various legs and found the leg that goes under/down the right rocker to the rear for the cargo lights, spare tire light and antenna relay, was shorted to ground. It was shorted behind the right cargo light. There is a small 2 wire harness going to the light and it was pinched shorting the hot to the ground wire. I pulled another wire through for the main harness, just to be sure and spliced it to the connector inside/behind the right rear cargo wall area and the vertical harness behind the wall panel by the rt. seat belt retractor. I then tied the cargo light HOT to it. I shielded it with plastic wire loom.
All seems well.......for the moment(knock-wood). The fuse isn't blowing and I see NO continuity to ground in the circuit.

Now to test various components and re-assemble this mess.

I've come to a conclusion.....Besides being the greatest car to drive, the people that choose to work on these "wonders" have to have a TON of patience and be into "SEVERE PAIN AND ANGUISH!"

O.M.G....

 

[Hib Halverson]

Indeed, a PIA to find that short but nice work "DonB". You make a fine electrical technician.

 

[DonB]

Thanks Hib. It wasn't my first rodeo,....but it was one of the most complex in quite a looooooong time.

Best Regards, Don.