Okay, loaded 89 RS convertible. The car started this problem intermittently a few weeks ago and today whatever was failing did. I live in a high moisture area, I get a sea breeze blowing over the car most of the day. I have lost the horn, headlights, door locks, pwr mirrors, and radio. Thats all power to the radio, no clock, no power antenna, no cd eject. I still have power windows, blinkers, gages and wipers. ECM is on a Painless harness so it is standalone from everything else. This happens whether the car is running or not. I am terrible at reading schematics. It does not appear that these items share a common ground. Could a fuseable link have died somewhere? I thought they only used fuseable links if no fuse was used? I see the horn, headlights doorlocks and radio appear to use relays. Could these relays share a common ground?
HELP!!!!

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Rob P
89RSconvtZZ4TPI Edelbrock Intake
SLP Dual Cold Air Intake 1 5/8" Headers Semi-Siamesed Runners, IROC
suspension, alum shaft. Numerous mods.
92Z28convt5spd (stock)
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

You've read this before, but I'll post again:

Sounds like fusible link "A" has gone bad. It powers the lights, door locks, power mirrors, tail lamps, and many more. Sounds like it was going bad, and now has gone bad. Fusible link "A" is on the back of the starter, and the way to check fusible links is to pull on them. If it stretches like a rubber band, its bad. If it won't stretch, its good. Also make sure it isn't loose. Fusible links can go bad after time, and you can get a new one at pep boys in there "electrical" section

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In my 89 RS the horn, interior lights, stereo, and power locks all went out due to one fuse.

 

As an update to interested parties, I checked the fusable links for continuity with my ohm meter and they are good. I also tested the 30amp breakers and they are good. I am not getting juice to the fuse panel. If I jumper 12 volts from the "battery" supply on the fuse panel over to the one pin of the 30amp accessories breaker, everything except the power locks work. Fuseable links are solid and don't stretch. Hmmmm.


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Rob P
89RSconvtZZ4TPI Edelbrock Intake
SLP Dual Cold Air Intake 1 5/8" Headers Semi-Siamesed Runners, IROC
suspension, alum shaft. Numerous mods.
92Z28convt5spd (stock)
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

Sounds like salt corrosion has messed up the fuse block, may have to take the fuse block apart and clean it or it would be faster just to replace it.

 

GM Tech mentioned that where the wire harness enters the firewall sometimes gets corroded. I work on boat lifts and davits here in the Keys and we have this great stuff called Corrosion X. We spray our electrical motors with the stuff all the time. Even tools we drop over the side in salt water. Saves them every time. Guess I'll pull that plug and clean all contacts.
Thanks for the reply.

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Rob P
89RSconvtZZ4TPI Edelbrock Intake
SLP Dual Cold Air Intake 1 5/8" Headers Semi-Siamesed Runners, IROC
suspension, alum shaft. Numerous mods.
92Z28convt5spd (stock)
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

Just to update you all, I pulled connector C100 apart, the firewall connector, cleaned the contacts, sprayed some Corrosion X on them and reinstalled. My problem cleared up. Apparently where fuseable link A entered the C100 into the fuse panel became corroded and failed.
Laters...

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Rob P
89RSconvtZZ4TPI Edelbrock Intake
SLP Dual Cold Air Intake 1 5/8" Headers Semi-Siamesed Runners, IROC
suspension, alum shaft. Numerous mods.
92Z28convt5spd (stock)
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!