94 LeSabre electric door lock problem

The electric door locks on my 1994 LeSabre stopped working a few months ago. I'd read that the most common cause of trouble with these was with a relay under the driver's seat, so I removed it today to take a look--not as much trouble as I'd imagined.

However, in this case, the problem wasn't with the usual suspects: the relay, the control voltages, or the switches. What I'm not getting at the connector that hooks to the relay assembly is the always-hot +12V (orange wire) from the 60 amp fuse that feeds the trunk release, door locks, and horn, according to the label on the under-hood fuse block.

I have not yet removed the fuse block to see if there's a bad connection at that end, but the trunk release and the horn work.

(I build Hi-Fi amplifiers as a hobby, so I investigated all possible electrical faults at the relay end of the harness such as bad grounds, connections, etc...)

What I don't have for this car is a detailed wiring schematic. Is there anything between the under-hood fuse block and the orange wire at the relay--like a connector or another fuse--that could be the source of the trouble?

Thanks!!

I have a 92 service manual. Usually the 92 and 94s are very similar. According to the book, the fuse for the power door locks is in the "relay center" which is under the passenger side dash behind the black shield. (Also, the under hood Circuit Breaker 4 is part of the circuit.) It is a 15 amp and is fuse 3. The Door Lock Relay Assembly is also in the same relay center but at the very bottom. It is directly below the area where the fuses sit. You unclip it and pull it towards you and then flip open the cover and remove the circuit board (should you want to replace it.)

If the 94 is the same, pull the black shield, check fuse 3. Check both sides of the fuse for voltage and also continuity to ground. To bypass the relay and see whether the fault is in the relay add a jumper between a known good 12V source and the B wire on the four-wire harness for the Door Lock Relay Assembly AFTER disconnecting the relay from the circuit (if that is possible.) If your door locks work with the jumper in place then replace the relay. My guess is that your fuse is burned out, but who knows. It could also be a bad ground from spot D on your four-wire harness.

I appreciate the detailed help, but I think that component locations for this circuit were changed by 1994. The relay center is on the engine side of the firewall protected by a removable black plastic cover, and the door lock relay assembly is fastened to the chassis under the driver's seat. The larger fuses are contained in two bays in this relay center under the hood.

There is also a fuse block inside the car, under the dash, on the driver's side, containing smaller value fuses, but none of these seems to be related to the door lock circuit.

My suspicion is that there may be a bad connection at the fuse block under the hood. There are several orange wires leaving this area.

Perhaps a better way to address my problem would be to ask for the best place online to download a factory wiring diagram specifically for my car.

I've seen some, but it seems to cost almost $30. Is there anything cheaper?

I have a Chilton's manual, but it only has a diagram of a "typical keyless entry" circuit.

According to the book, the fuse for the power door locks is in the "relay center" which is under the passenger side dash behind the black shield. I appreciate the detailed help, but I think that component locations for this circuit were changed by 1994. There is also a fuse block inside the car, under the dash, on the driver's side, containing smaller value fuses, but none of these seems to be related to the door lock circuit.This did not change in 94, still one located under the passenger side dash!

This did not change in 94, still one located under the passenger side dash!

I stand happily corrected! What a bizarre place to hide a fuse block. Thanks to both of you. I practically had to do a headstand inside the car to see it.

I did, in fact, find that the 20A fuse for the door locks was blown. Unfortunately, when I inserted a new one, it immediately blew, too, but at least I now know what the problem is. I guess I've got to remove the driver's seat again to get at the relay assembly and harness to see if the short is in the wiring upstream or downstream from the relay or in the relay itself.

If the short is somewhere in one of the doors, I may just live with manual locks :-)

David