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First check for the easy stuff like the fuse, then check cables.

I'd suggest trying a switch swap for the passenger side as i've had switch failures (in fact both on one car).

However, it's quite likely that it's a broken element. You can test for this by sticking an ohm meter across the connector (yellow and black if I recall) at the seat. It should be about 2 ohms, if not and it's open circuit then you need to remove the seat cover and fix the break by soldering in a short piece of wire.

It's not that difficult, you just need to remove about half a dozen wire clips from underneath the seat and you can then lift the cover off from the front.

A break is likely to be on the seat squab so there's no need to remove it completely and you can usually find it pretty easily by just finding the burnt section of the seat foam.

Total job time is under 2 hours and that's being very generous. I think I did my Aero seat in about half that and having done a couple of seats, it's the same each time, just a small break where the element wire has weakened through wear caused by the drivers botty.

See also:-

http://www.swedishwrench.com/seat.htm

http://quasimotors.com/heated_seat_repair.htm

David.
 

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Hi David

My drivers seat is also not working, though the switch is fine. I am going to try and find the break in the squab, but can I ask if you managed to do it with the seat in situ, or was it easier to remove the seat from the car.

Thanks

David
 

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Hi I've just fixed the heater in the seat base from on of my seats. I would recomend removing the seat it's much easier, however you could simply turn the seat upside down in the car, this would save you having to remove the seatbelt.
You will need the seat upside down in order to remove the clips that hold the cover to the base. I followed Quasimotors directions and it really doesn't take that long Here is a pic of the repair I did to my seat heater element


Thats the wire stripped back and with the flux applied ready for soldering. I didn't put too much solder on so that the wire remains relatively supple. I then covered the wire with a thin strip of good quality insulating tape and it now works fine.
HTH
cheers C
 

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The most common reason for non-working heated seats is a broken element in the seat base heated pad.

To prevent damage never sit in the seat with keys in your back pocket. Never kneel on the seat. Be careful when putting boxes/other objects on passenger seat.

Good luck
 

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Naranto, I did take my seats out, it's not hard and does make it much easier.

I also soldered in a length of wire about 1cm long so that the new join wasn't going to be stressed and just slipped a couple of cm of heat shrink sleaving over it to give it some strength at the join.

Once I did this, I then discovered that both my heater switches in one car were faulty, the one in the drivers seat I had just repaired was locked on. Relay was just energised all the time. I didn't realise until my first long journey when the seat would not turn off and i ended up going through Reading on a frosty morning, still 0 degrees outside, with the window down and sweating.

I'd like a "Heat boost" override though for the very cold mornings so that the thermistor can be overriden to keep full power to the seat until you're toast!
 

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cdcarlsson, was just thinking about this but is that suggestion of 2R right? I'd have thought it would need to be much higher on the basis that when warm, the thermistor resistance will be lowest already so adding just a couple of ohms surely isn't going to make much difference?

David.
 

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Yep, the back of the switch unit is the place I spiced in the resistor at. Two ohms is about right, by trial and error that's what we ended up with on my friends seat that wasn't hot enough for him. He doesn't complain now though!

Nick.
 

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Interesting!

I measured my thermistor with the seat cold this afternoon and it was ~ 1300R

When hot, this dropped to around 650R, that's why I wondered about a couple of ohms making any difference, I can see that inclusion of 100R or 200R will make a difference but is your friend sure that the new feeling isn't a placebo effect?

I might get round to wiring in a pot so that I can set a max hot value and measure that or maybe even make it a trim pot at the back of the switch.
 

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Had a word with my friend today and he remembers us ending up with twelve and a half ohms inline. This allowed his seat to warm up by a further three degrees before switching off (measured with a calibrated thermocouple), just right for his bad back. Much more resistance and the seat never turned off, much less and it didn't have the desired effect. This might be different car to car, his seats wern't as warm as mine to start with which is why we went down the road of altering them.

Nick.
 

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I have a 97 anni. Same colour and the same year although it has the proper 2.3 FPT engine. Mine does not look quite the same now as I have fitted an aero interior. One thing that puzzles me is what happened to the wooden gear shift knob? All anni's had them?.....

David!
 
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