I think I've narrowed down my battery drain issue to be the power door lock system - either the lock relay or the ground wire to it from the actuator in the door.

Over night, my battery would drain down to 2 volts. And the power door locks magically stopped working as well - even with a fully charged battery. After recharging, I pulled fuse #8, and the battery was fine after 12 hours. I also noticed that when the fuse was in place, I could not manually unlock the 3 doors - the motor in each door was holding the locks down. I think this is due to the relay being continually engaged.

Assuming it's the relay, what is the best way to get at the relay? Remove the radio AND center vent? I've not been able to find any replacement relays via the usual suppliers. Any suggestions, or are they repairable?

Thanks.

Thanks for the quick responses. You guys were spot on. I should have realized that a relay rarely, if ever, sticks in the engaged position. Duh!

The switch around the lock tumbler showed evidence of a previous repair, and the unlock (center short metal strip) had come loose from the switch housing. I could not reliably get the metal strip to stay in place. So rather than take the chance that it will come loose and drain the battery, I decided to remove the switch from the circuit, and I'll look for a replacement and install when I have more time. (those replacements are darn expensive!) And the wires were frayed as well.

In the mean time, the power locks still work using the door mounted plunger switch. Just need to remember to lock them before locking the car.

Thanks again!

Fairly cheap to add keyless. Then you have the lock in your pocket.

http://cleanflametrap.com/keyless3.html
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Art Benstein near Baltimore

Engineering says: "Essentially complete."
Engineers meant: Half done.

I agree with Art, it is likely the key OR lock knob switch inside the driver's door.

Remove the driver's door panel and determine which of the offending switches it is. If it can't be fixed, disconnect that one so you can still use the other.
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1980 245 Canadian B21A with SU carb, M46 trans, 3:31 dif, in Brampton, Ont.

With Phil I agree. This is not the relay. It is at the key and lock knob switch inside the driver's door. Very common trouble, as in "they all do that."

Remove the door card and find the red, green, and black wires at the lock switches. Most use "liquid electrical tape" to repair them.

For a shortcut to repair and confirmation of the diagnosis, just above your left knee is a three-pin connector leading to these switches. Disconnect it there and kiss your battery drain worries goodbye. Save your knuckles and leave the relays (very reliable cube relays) where they are behind the center vents. Eventually, you'll have to go there to repair the socket in which the main headlight relay resides.


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Art Benstein near Baltimore

Engineering says: "Preliminary operational tests are inconclusive"
Engineers meant: The darn thing blew up when we threw the switch.

Hi,
Here are some diagrams that you may already have.. It shows the location of the relays and power routing.
http://www.volvowiringdiagrams.com/volvo/240%20Wiring%20Diagrams/TP31054-1%201987%20240%20Wiring%20Diagrams.pdf

You may want to consider that the key lock switch, in the drivers door, has frayed wires in the harness around the switch. If those are touching one another it may be telling the doors to always lock.
You will have to pull the door card to inspect the situation in there. I have seen a many those lock switches, in the junkyards, with rotten insulation.

Relays rarely hang closed on as they are more likely to quit working all together. You might still be on the right track as nothing is impossible after this many years.

Good luck

Phil