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Sal Lubrano

Active Member
Joined
Apr 26, 2002
Messages
1,235
Hello, I am faced with an expensive repair and I would like your opinions if this would work and what would you do. My 1999 Jeeps grand has heated seat except the passenger side has gone bad. I have traced it down to a bad thermistor. The good seat in the morning at 65 degrees reads 9.13 ohms across the thermistor but the bad reads 138 ohms. I have checked the resistance across the heating element as well and they were good in the bottom pad and top. I called jeep and her eis the funny part. The thermistor and heating elements are inside the padding along with the leather. The price is $600. Yeah that is what I said! I am now on a mission to replace the thermistor. After some research I have found out this.

The temperature sensor is a Negative Temperature
Coefficient (NTC) thermistor. One temperature
sensor is used for each seat, and it is located on
the seat cushion heating element for all models.
The seat heating elements are sewn into the seat
cushion cover trim and seat back cover trim units.

I am taking for granted it is a 10 ohm thermistor. Due to the fact a 10 ohm will be 10 ohms at 75 degrees and I read the good one at 65 degrees and I had 9.13 ohms. Took the seat cushion apart and this is what I found if you look at the picture. The thermistor is connected to the black wires. It is a long piece of wire which goes up and down the bottom cushion. I want to solder in a new one but I am on a hunt for a suitable replacement. I have found this company. I was thinking about using the thin film one they have but it will not weave through the seat. I have no proble cutting the foam more and running a new wire and then using some glue to hold the foam and wire but where would I find this thermistor type or do you think the film type would work? Any input would be a great help. Thank you.

ECC Division | Selco Products
 

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Sounds like a reasonable option. Give it a shot. Is the part expensive?
 
sounds logical to me too.im not a jeep expert,but on my wifes Tahoe,the passenger heated seat wont work without the passenger seatbelt engaged.do you have a schematic? her control box was bad.....never fixed it.
 
Selco makes good stuff, but I would expect a thin film thermistor to be way too delicate to survive in a seat. Can you go junkyarding for one?
 
A replacement thermistor I was looking at is very cheap, only a few dollars. I do have a schematic but it is in pdf and I don't know how to copy it here. The thermistor has 5 volts comming in to it and depending on the resistance value (which is based on the temperature of the cushion) the amperage will change telling the control module the temperature of the seat. But I am having a hard time finding a suitable repacement for the thermistor. I live in Brooklyn and we don't have junkyards for many miles. The nearest one which migh have a jeep has to be two staes away.
 
Well you can always try the thin film one, and if it breaks you will just be back where you are now :-). I'd put it about an inch from one end of the heater wire so it doesn't take tooo long to see the heat. Get a short piece of copper tubing and lightly crush it almost flat so the thermistor will just fit inside, goop it up with heat sink compound and insert, then seal the ends with epoxy. That will protect it but still give decent thermal performance.
 
Pm me the last 9 of the vin where i work we are a jeep dealer their was a recall on heated seats but since im a vw tech i dont know the years can check and see if this has it with my warrenty admin you may be lucky
 
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