Testing seat heater switches

[6670charger]

I'm never quite sure if my seat heaters are working on my E30.  I'd like to test the switches to make sure they're actually sending current to the pads in the seats.  I assume that if I pull the female connector they're plugged into out just enough to put a test prong onto the leads under the switch, I should be able to get some sort of reading on a meter when I turn the switch on since they'll still be connected?

[mkoepp]

I took look in my E28 Bentley and did not find anything on the heated seats. It's late and it's probaly there but if you don't have a Bentley for your E30 here is a link to the Electronic Troubleshooting Manual (ETM).

 

http://wedophones.com/BMWManualsLead.htm

 

I think there might be a relay involved with the heated seats. That would be a good place to test power, ground ect...

 

Good Luck.....

[6670charger]

OK, found it in the manual.  Now just need to figure it out.

[jc43089]

FWIW my e36 seats do not heat unless someone is in the seat, not sure if it's supposed to be like that.

[mkoepp]

I don't think that is normal for the seats. If both seats are doing not working until you sit on them maybe you have an upgrade. Your car does not have an airbag so I don't think without looking at the online ETM your car would a weight activated heater. After thinking about it I don't think even the newer cars have this. What good is remote start if your seats are still cold  . 

 

Here is a link to the ETM for your car. 

http://wedophones.com/Manuals/BMW/1994%20BMW%20318i-s-c%20-%20320i%20-%20325i-s-c%20%20Electrical%20Troubleshooting%20Manual.pdf

 

Here is a link on a DYI repair.

http://www.bimmerboard.com/forums/posts/830280

 

I had a 94 325i and know the car somewhat but I did not have heated seats.

 

 

I hope this helps. Gitem fixed before you need them! 

[jc43089]

I thought it was strange but both are the same, neither seat will heat until someone sits in it.  I don't see anything in he ETM that would cause that either, maybe they have open spots that make connection with weight on the seat.  I don't drive it in the winter so no big deal.  Thanks for the exact ETM for my car though, very handy.

[6670charger]

Thanks.  That at least helps me understand how the seats come apart should I have to go that route.  I have power to the switches, as they light up when I turn them on.  Just don't feel any real difference in seat temperature when the switch is in the on position. i assume that the forward-most switch on the console is for the driver's seat.  Guess I should make sure of that as I've never found any reference anywhere, even in the owner's manual that specifies which switch is for which seat.  I've tried both switches, though, and neither seems to make any real difference in seat temp.