1984 SD Elec. Vac pump/door locks
 

Hi guys. I have a new to me 1984 300SD. The door locks are not working as they should.They will lock but not unlock. I tested the electric pump in the trunk. I have voltage there but it will not turn on. Can anyone tell me what activates the pump?? Also is the vac for the door lock completly seperate from the rest of the vacuum system? Thanks Tom

Door lock vacuum is seperate fro the the rest of the system on an SD. Don't forget it also includes trunk lock and fuel door lock.

Thanks for the info. I still cant get the pump to turn on??? Bad pump? Tom

The pump has a mechanical valve that switches the lines between vacuum to lock and pressure to unlock. Sounds like that's where the issue might be if it locks but won't unlock, or the unlock signal from the key lock isn't getting to the pump. The pump gets +12V through the blue wire to lock and +12V through the yellow wire to unlock. I don't know if it's a continuous or momentary signal.

Sixto
87 300D

Junk in the Trunk
 

I have had an issue with my trunk not unlocking. It has only happend 3 times but always at the worst times. all the door locks work fine, the fuel door has never worked as far as i know. What would cause this? I sprayed some brake cleaner in the lock catch and then some light oil. I had a case of water in there that froze because I could not get to it.:eek:

What model/year do you have?

Does it have the factory alarm system?

It is an 84' SD. No alarm as far as I know.

There is an alarm. we have it on our 84. wife was driving it when we first got it, and the horn kept beeping. she went to the indy we were using and they put the key in the drivers door, turnit, and the horn shut off.

Charlie

"There is an alarm. we have it on our 84. "

the alarm was optional on non north american models, babe. he might have a grey market import. there was a ***** ton of grey market sd's back in the heyday

I believe mine is a grey market import, with velour interior so it's still up in the air as to whether you have the factory alarm. It's real easy to find out as all you have to do is lift the front passenger floor mat and look for a "black box". From what I've read, here on the forum, the driver's door lock has a special micro-switch for the alarm and it tends to get gummed up with a combination of dirt and humidity.

If you have the alarm, I can PM you with how to disable it and what you need to unlock the trunk.

I will check for the black box in the next couple days. Thanks for the heads up.