Power seats & door locks not working...

[pig_iron]

Well the first startup of the spring gave me several surprises. One was that my 2 year old Optima battery was so dead I had to take it into AutoZone to have them test it. It registered nearly zero (so much for "deep cycle") and they had to slow charge it for 2 days. Got it back, hooked it up, car started right up...minus a few features. The power seats and door locks no longer work. I checked the fuse for the seats and before pulling it, noticed it was frying hot. Bought a new one, sparked as I put it in (car off), and still no movement. Tried the old one, same thing. The fuse for the door locks underneath the glove compartment was fine, but changed it anyway...still nothing.
I've taken the seats out looking for a bare wire somewhere, pulled up the carpet, taken apart the center console, taken the stereo out, and the housing for the power seat controls looking for a short somewhere. There is a slight smell of something burning somewhere, but I have no idea where it is. When the car is running and I put the new or old power seat fuse in, the engine slows a tad and the lighting dims, along w/ the sparking and crackling when I insert the fuse.

Any ideas? I'm actually putting the car up for sale because of these fantastic economic times and I just got laid off from my job. Won't be too easy selling it for starters, much less w/ seats that don't move.

[GOLDCYLON]

Check the seat switches for the air bolsters motor and movement switch. One of them is jammed into the on postion always. Which is why the battery died as well. The burning smell and the smoking hot fuse make this the likely issue. Good luck. GC

[pig_iron]

Both seats are completely out. Bolster buttons and switches are ok and the seats work properly through an outside battery source (out of the car). Even w/ no seats in the car, nothing hooked up, that 30 amp fuse crackles and sparks when I put it in, and gets hot after 30 seconds...with no seats and no activity whatsoever.
:dontknow:

[GOLDCYLON]

Do you have a top post battery/ side post combo? If so top post might be grounding against the frame?

[Jeffvette]

Welcome to electrical hell.

Both the seats and the door locks are powered by the silver 30 amp circuit breaker in the fuse panel. What you are going to be looking for is a short to ground. First, but a service manual with the electrical supplement. And go from there.

[pig_iron]

Welcome to electrical hell.



Yep. The problem was the main feed under the center console to the power seats. I took apart the side of the console to find a melted mess of electrical tape and a burn mark on the insulation between the chassis and the feed wires. After cutting apart the melted tape, the 3 main wires still appeared to be in working order and connected to the harness, but there were 2 thick, knobby looking bare wires coming from each side of the harness that looked like it might have been a fuseable link, as the ends were slightly belled. They clearly were responsible for the mess. I don't know why a fuse was necessary at this location if that is indeed what it was.

Anyway, the melted garbage has been stripped away, the original wires still work (tested w/ a meter) and the mystery belled-end wires were cut off. Put the 30 amp back in the fuse panel & no sparks or noise, and it stayed cool. And somehow this brought the power locks back to life. Now all I need is a week to but this mess back together...

Never had a car w/ such a complex and troublesome electrical system. Kudos to the engineers...

[1990 415]

the joy of ownership. fortunately you fixed rather quickly with very minimal expense.

[xxxscimitarxxx]

maybe an old thread but i have some of exactly the same symptoms with my 92....both seats lost all function (infact still havent fixed as car has been 12mths off road for brake reasons)

that fuse/relay in the passenger side fuse comp fizzes and gets damn hot without the seats doing anything.

the only issue l have tied it to was the recline swith on base of seat under your right thigh....mine went up in smoke!....seats worked for a while then both suddenly stopped altogether

so seems from your issue that it could simply be burned out wiring that has shorted ....now lve got something to go look for