KlausC Posted March 30, 2008 Report Share Posted March 30, 2008 Is there a write up on how to trouble shoot the seat heater on my 1995 854? The passenger side works just fine and the switch does light up.I really don't want to uncover the seat cushions if I don't have to. Both bottom and backrest do not work. I did not test the wires yet for voltage.Thanks Link to comment Share on other sites More sharing options...
Ozark Lee Posted March 30, 2008 Report Share Posted March 30, 2008 This will help you out.Look under the seat, on the right hand side as you look at it from the footwell, and locate the power connector for the seat.It is the large white connector with the Yellow/Red wire and the Black wires.Use a Voltmeter and, with the seat heater switch on and the key on, check for battery voltage between the Yellow/Red wires and the Black wires. If it measures good there it means that the switch is good and the wiring to the seat is good.You next need to locate the heater pad plugs, they are just below the front edge of the seat, they are both 2 conductor connectors. One connector is gray and the other is black.They are pictured here:Backprobe the red wire on the black connector and check it for battery voltage as well, the black wires on the power connector are a good ground point for the meter.If you have good voltage there it means that the thermostat and its circuit are good. If you don't have voltage there it means that the thermostat is bad (not likely) or the wiring to the thermostat has come unplugged (more likely). The thermostat is located near the rear of the bottom seat cushion and it has a Red wire and a Red/White wire going to it. Plugging it back in is tricky and is best accomplished from the back seat and having someone sitting in the seat - that someone will get goosed a bit.Assuming that the voltage is good on the red wire next move to the yellow wire. On a normally working system you should read voltage there but it will be less than full battery voltage.If you read full battery voltage on the Yellow wire then the seatback heater element has burned out.If you read no voltage there then the seat bottom heater element has burned out....Lee Link to comment Share on other sites More sharing options...
KlausC Posted March 30, 2008 Author Report Share Posted March 30, 2008 Thanks Lee!! I am off to the garage... Link to comment Share on other sites More sharing options...
KlausC Posted March 31, 2008 Author Report Share Posted March 31, 2008 This will help you out....LeeAnd it did. Still no heat, but I didn't fix anything. I check the black plug hooked to the front of the seat and get strong voltage. The grey connector, no voltage. Also none at the little one on the rear seat bottom.I was checking the seat bottom plug to make sure it had not just come loose, when it fell into my size 15 mitt. I had to take the seat out and tilt it forward to realize that I bent one of the connectors 90 degrees when I tried to put it back on the first time. My hands were not built for that!!!Now, if there is no juice at the grey connector????? My brains are totally shot. Link to comment Share on other sites More sharing options...
Ozark Lee Posted March 31, 2008 Report Share Posted March 31, 2008 If you are getting voltage on the red wire on the black connector but not getting voltage on the Yellow wire (either on the black connector or the grey connector) it means the seat bottom pad has burned out. That is the one that seems to burn out the most. Since you have voltage at the black connector that means your thermostat is OK.My drivers side seat bottom is burned out as well and I need to order a new pad. The part numbers are different depending on whether you have leather or not.I show part number 9174640 for leather seats and 9174641 for cloth seats. I think that is where I screwed up. I bought a used foam cushion - the foam was great and improved the feel of the seat - but the car it came from had cloth seats. I think they have different resistance levels depending on the type of seat cover.Either way, the pads range between $42.00 and $43.00 at volvopartsclub.com. Since shipping is free over $50.00 I'm thinking I will need some crush washers or oil filters to get the bill over $50.00. Figure on leisurely 3 hours or so to remove the bottom seat cover and replace the pad. It isn't that bad of a job and I detailed it in a writeup in the database over on Matt's site.Best of luck with it....Lee Link to comment Share on other sites More sharing options...
KlausC Posted March 31, 2008 Author Report Share Posted March 31, 2008 That is what I suspected. The seat got real hot the last time I drove the car, and my 235 butt did not help matters any Thanks for all of the help. Link to comment Share on other sites More sharing options...
dykaar Posted March 31, 2008 Report Share Posted March 31, 2008 A warning about the seat thermostats. My wiring failed at the thermostat, and after the repair, I apparently didn't get it pushed all the way back into the foam. The seat got REALLY hot, for a little while, then popped. When I had the seat out to replace the heater pad, I was able to reinsert the thermo switch fully since I could now see it from above. Link to comment Share on other sites More sharing options...
KlausC Posted March 31, 2008 Author Report Share Posted March 31, 2008 A warning about the seat thermostats. My wiring failed at the thermostat, and after the repair, I apparently didn't get it pushed all the way back into the foam. The seat got REALLY hot, for a little while, then popped. When I had the seat out to replace the heater pad, I was able to reinsert the thermo switch fully since I could now see it from above.Thanks for the heads up! I will probably not replace the heater until it warms up. It makes the leather and vinyl combination easer to work with. Besides my daughter, her car, won't get home from school until May. My lard butt doesn't really need heat Link to comment Share on other sites More sharing options...
Seagrams Posted March 31, 2008 Report Share Posted March 31, 2008 Thanks for the heads up! I will probably not replace the heater until it warms up. It makes the leather and vinyl combination easer to work with. Besides my daughter, her car, won't get home from school until May. My lard butt doesn't really need heat There was a recall on these (maybe for 94 too, but def. for 96) that is due to a problem that the OP spoke of about the thermostat giving out... apparently it was a fire hazard. Check with a dealer and give them your vin to find out if A.) the recall applies to you and B.) if you car has gotten it already. Link to comment Share on other sites More sharing options...
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