Irregularly Heated Seats

Post by **jtp** » 09 Nov 2007, 19:31

I'm as new to heated seats as I am to Volvos so maybe this is normal but my s70's driver and passenger seats get hot and then stop heating, then start again, etc.... every five minutes or so. I told my wife it was possibly how they regulated the temperature before I experienced but now I'm not so sure. Is it a loose connection or is this just another Swedish eccentricity?

Post by **JRL** » 09 Nov 2007, 20:02

That's about how they work in 98-00

Post by **Maxbaby** » 09 Nov 2007, 20:11

If you were to look way underneath your bottom seat cushion, you would find the thermostat which sits inside the foam of the cushion. It senses the temp and shuts the power off to the heater pad at the "appropriate" temp, then turns it back on. Dunno if its a simple timed off period or whether its looking for a particular temp in the foam itself before it turns back on, but either way, they do what yours are doing.

Post by **JRL** » 09 Nov 2007, 20:48

850's never got hot enough, 98 thru 2000's are this way, too hot or not hot enough, 01's are all over the pplace, 02 and newer they got it right, something that's been offered in cars for YEARS

sixdown · Post by **sixdown** » 10 Nov 2007, 16:48

They certainly get very hot in my '98 S70, and yes, they also switch on and off. If they don't, I assume you can see smoke...

Thats what I love about Volvo's. They've had all these options that newer cars have only just begun to offer. I mean, heated mirrors?

Post by **jtp** » 12 Nov 2007, 07:37

Wow, I actually diagnosed a car problem correctly, you know you've got a good car when your main concern is the temperature of your bum when you're driving. Thanks for the help.

zenmervolt · Post by **zenmervolt** » 12 Nov 2007, 09:47

sixdown wrote: Thats what I love about Volvo's. They've had all these options that newer cars have only just begun to offer. I mean, heated mirrors?

Back in 1983 the Porsche 944 had heated mirrors. I think it was a fairly common option on Northern European cars and it just didn't get to the US until later.

It's also worth noting that by the time of the 850 series, Volvo was moving decidedly upmarket in the States so part of the reason that these cars have options that are only now becoming common is that they were high-end vehicles in their day and it's simply taken this long for the technology to trickle down into more mass-market vehicles.

Back to the heated seats, they are also tied into the cabin temperature sensor. For example, if it's 90 degrees in the car and you turn on the seat heaters, I believe they will not actually come on, while if it's 45 degrees they will come on at a low setting, and if it's 15 degrees, they'll come on at a high setting. (Temperatures are all guesses to provide an example and may not correspond to actual system thresholds.)

The owner's manual is rather skimpy on details, saying only:

"The heated front seats can be switched on and off as required. When switched on, the system senses the ambient temperature and regulates the level of heat applied. When the optimum temperature is reached, the heating switches off automatically."