6.17 - Seat Heaters ( Alan Heartfield,
February 6, 2003
The seat bottom is easily removed by removing the single phillips screw in the front of the seat. Lower the seat back to at least the half way back position. The seat cushion can then be lifted up, front first. The red connector for the switch on the side of the seat cushion must be disconnected first. To disconnect these connectors, squeeze the two protrusions on the sides of the connector, and pull the plug and socket apart. The seat can now be raised to about 45 degrees, giving clear access to the motors and heater connectors.
There are two heaters in the seat. One in the cushion and one in the back. They are wired in series, so if either heater quits, neither will work.
Remove the connectors from their clips and disconnect the ones that go to the seat cushion. There will be another red one for the cushion heater, a yellow one for the back heater and a green one and a black one. The seat cushion can now be removed from the car.
Now is a good time to clean up under the seat and make sure the motors are all running freely. I put some dry graphite lubricant on the actuating rod threads.
Turn on the car ignition and the seat heater switch. Check for voltage at the red connector for the seat heater at the end that remains in the car. There should be full battery voltage here. If not, then you have found the problem.
Jumper between the two pins on the yellow connector and use a good ohmmeter to measure the resistance between the pins on the red connector for the seat heater. There should be approximately 2 ohms. If so, then the problem is with the seat back heater. This was my case, so I now had to access that heater.
First remove the small phillips screws on each side of the seat back. On the left side of the seat is a larger phillips screw holding a plastic hole plug. Remove this also. Get into the back seat of the car and pull down and back on the seat back with the map pocket in it. The whole back of the seat will come off, exposing the motor and heater wiring.
Now remove the clips so the seat front cover can be carefully peeled off towards the front of the car. I also released the two lower clips holding the diaphragm. As the seat cover comes off, you will find a couple of green bungee cords that keep the cover taut. Release the one on the left from the rail at the lower rear of the seat back.
The seat cover does not have to be entirely removed. Just loosen the frontleft side until it can be lifted up sufficiently to see the heater. Two black wires feed the heat from the bottom, centre, front of the seat back. There is a layer of cheesecloth covering the seat heater grid.
In my case, a section of the cheesecloth was charred about 3" up from the seat back bottom. I cut a slit in the cheesecloth so it could be peeled back, and found the connection between the black wire and the grid had melted. I cut away the damaged wiring on both sides of the problem area, and using crimp connectors and a short length of SXL wire, bonded them together again. A better choice would have been some teflon wire. SXL is a high temperature wire with an insulation that will not support combustion. I had some on hand, but no teflon wire. When crimping, do not use the cheap style of crimper that clamps the crimp between two arcs cut in the tool. Use a crimper that has an arc and an opposing dimple such as the Thomas and Betts tool. Otherwise, cold flow will not occur and the crimp will just get hot and you will have the same problem all over again. Alternatively, solder the connection, which is what Jaguar (Recaro) did.
Test, reassemble, and toast some buns.