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Discussion Starter #1
1987 300D 271,000 miles

Back Seat head rests will not go down. What is the best way to search for a vacuum leak? It is vacuum, right?

Also, Driver and Passenger rear windows work fine when they work, but then keeps blowing fuses every couple of days now. The other two windows work fine. Whats up with this? Any clues?
 

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Yes, it is vacuum for the headrests. When mine were not working, the culprit was the brown (if I remember correctly) vacuum line going into the firewal had come loose while I was messing with something else.

A shot in the dark for the fuse problem, you could have a regulator/motor going bad. Are the windows slow? Try making sure the reglator glides are well lubed, so that the motor is not working harder than it is designed to.
 

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As Cracker928 said check the line at the firewall, to see if it is disconnected. If your 300d works the same as a 300e, you can pull the bottom portion of the rear seat, and look on the drivers side, under the sound suppresant, you will find a solenoid(small black box) attached to the body with two phillips screws. This solenoid should have two vacuum hoses attached, if you remove them from the solenoid and attach them together, your headrest should go down, if this works, then you will need to troubleshoot the electrical side to see if you are getting voltage to the solenoid, if so, the solenoid may be bad. Keep us posted on what you find.

Ken
 

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If I could answer you both...First of all thank you. I will try what both of you have suggested.
To answer on the windows, they work perfectly, until it blows the fuse. It always blows in the up position. I talked to another tech, and he suggested the wiring to the motor may be brittle since it works perfectly, when it works.
Thanks again.
I love the FORUM!!!

SolarAngel
 

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Discussion Starter #5
vacuum response

Gentlemen,
1987 300 D
I took out the back seat, and found the solenoid with the white air line back to the headrests. I bypassed the solenoid to no avail. I ended up crawling into the trunk, and popped the spring lock on the headrests themselves. They are down for the first time in 5 years!
I can pull them up and they lock in place, so I guess I'll just leave them down. There must be a vacuum pump out somewhere...do you know where the vacuum pump for the headrest is located?
Is there one vacuum pump for the whole car? I also found a pump under the back seat on the passenger side. do you know what THAT is for?
Any help would be great.
Thanks.
 

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There are two vacuum pumps. One is on the engine and the other is the one you found under the seat. The one under the seat does the locks, and the one on the engine (front and center) does pretty much everything else, including the headrest. I believe the engine has to be running for the headrest button to work. If you in fact are not getting vacuum to the headrest, your performance might be suffering due to a leak as well. Time to get a mityvac and check all the connections....
 

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Discussion Starter #7
Cracker...

Will check out the Mityvac when I can. The Home Owners Assoc are pissed at me for doing too much work on my car. TIME TO MOVE!
I could spend all day working if they would let me.
Looks like I'll be out of commission for a while.
Thanks...
 

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Discussion Starter #9
The car was running when I bypassed the solenoid. Either the solenoid is bad, the pneumatic tubing is bad, or something else I haven't thought of...

It looks as though I'll have to get that vacuum test kit and chase it down.

Thanks!
 
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