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Discussion Starter #1
Hi

I have asked many questions in this forum in the past year about the possible reasons for temp gauge problems. The symptoms on the car was that the temp gauge stayed at 8 o'clock position at times, 9 o'clock position at other times. Sometimes it would even randomly jump up and down between the two. I changed the thermostat, the temp. sensor near the thermostat and changed the coolant. It didn't help, the problem got gradually worse.

On a Swedish forum (www.saab9000.se) I found a thread where a guy had documented how he fixed the instrument cluster in his car. Apparently this is a very common problem in later 9000's sold in Sweden. Apparently this problem is not common in the UK or America as most temp. gauge problems there disappear after a thermostat change. At least I got that impression reading these forums. Maybe the units with the metric dials differed also on the inside from the units with the imperial dials. But just in case somebody over there has similar problem to mine, I want to post the link here that shows the fix.

http://web.telia.com/~u33227289/saabtemp.html

It's in Swedish but the pictures tell it all. The red marked screws in puctures 7 to 9 should be removed so that the temp/gas meter module is removed from the cluster. Thdere are two more screws that bolt the module to the cluster that are not shown there but they are pretty straight forward. Then you also take off the temp/gas meter module from its housing by the 5 screws shon in picture number 10.

On picture 11 you see 8 nuts that are marked in red rings. The four on the right are for temp meter, and the four on the left are for gas meter. Take them off, making sure you noted down where the taller ones and the smaller ones go. There are spacers underneath them, and it is the spacers that are causing the problem. Unscrew the nuts, get rid of the spacers. Sand the sides of the nuts that will contact the card underneath. Screw the nuts back. I also put some (very little) soldering paste between the nut and the card and then soldered where the nut meets the card after I screwed it back.

Now the temp. meter on my car sits at 9 o'clock position when driving, and a little over 9 when idling in traffic. The erratic readings, and needle jumping has disappeared.

Naturally you should change your thermostat first if your temp gauge stays low, it is the most likely reason.

This fix will probably also cure similar problems in gas gauge.

There are instructions available on this forum on taking the instrument cluster out. You should not turn on the ignition when the cluster is off, or your SRS light will come on. If you have airbag on the passenger side things are more complicated. I only have airbag on the steering wheel so I don't know.

Berk
 

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so it's a ground problem?

you could run an additional wire from the gauge to the cluster, maybe under the same screws, if the nuts don't clean up as well.

the spacers are made of phenolic or plastic or something insulative?

good info!
 

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Discussion Starter #3
No, I do not think it'a a ground issue. The spacers some kind of metal, the material looks very cheap I should say. Their job is probably to keep the circuitboard beneath from damage in case the nuts are overtightened. The nuts on the temp gauge on my car were pretty loose, which probably opened the circuit for a fraction of a second at times. That would explain the needle jumping around.

The spacers may also be for calibrating the temp meter so that it points to exactly the middle point given a specific voltage. Then they should be conductive, but with some resistance. When you take the meter out, you see there are three dots, one at the bottom©, one in the middle and one at the top (H), which are hidden once you mount it back on. I think the middle dot is where the needle should point if the engine is running normal. After I removed the spacers the needle on my car is pointing a little above the middle at times. You can actually see the needle going back to 9 o'clock position when the thermostat opens. But this is preferable to erratic needle movement I had before. I am not knowledgable on electronics by any means and this is just a guess.

The problem with the spacers was that they were not holding the nuts tight.
 

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Hi

I have asked many questions in this forum in the past year about the possible reasons for temp gauge problems. The symptoms on the car was that the temp gauge stayed at 8 o'clock position at times, 9 o'clock position at other times. Sometimes it would even randomly jump up and down between the two. I changed the thermostat, the temp. sensor near the thermostat and changed the coolant. It didn't help, the problem got gradually worse.

On a Swedish forum (www.saab9000.se) I found a thread where a guy had documented how he fixed the instrument cluster in his car. Apparently this is a very common problem in later 9000's sold in Sweden. Apparently this problem is not common in the UK or America as most temp. gauge problems there disappear after a thermostat change. At least I got that impression reading these forums. Maybe the units with the metric dials differed also on the inside from the units with the imperial dials. But just in case somebody over there has similar problem to mine, I want to post the link here that shows the fix.

http://web.telia.com/~u33227289/saabtemp.html

It's in Swedish but the pictures tell it all. The red marked screws in puctures 7 to 9 should be removed so that the temp/gas meter module is removed from the cluster. Thdere are two more screws that bolt the module to the cluster that are not shown there but they are pretty straight forward. Then you also take off the temp/gas meter module from its housing by the 5 screws shon in picture number 10.

On picture 11 you see 8 nuts that are marked in red rings. The four on the right are for temp meter, and the four on the left are for gas meter. Take them off, making sure you noted down where the taller ones and the smaller ones go. There are spacers underneath them, and it is the spacers that are causing the problem. Unscrew the nuts, get rid of the spacers. Sand the sides of the nuts that will contact the card underneath. Screw the nuts back. I also put some (very little) soldering paste between the nut and the card and then soldered where the nut meets the card after I screwed it back.

Now the temp. meter on my car sits at 9 o'clock position when driving, and a little over 9 when idling in traffic. The erratic readings, and needle jumping has disappeared.

Naturally you should change your thermostat first if your temp gauge stays low, it is the most likely reason.

This fix will probably also cure similar problems in gas gauge.

There are instructions available on this forum on taking the instrument cluster out. You should not turn on the ignition when the cluster is off, or your SRS light will come on. If you have airbag on the passenger side things are more complicated. I only have airbag on the steering wheel so I don't know.

Berk
Is there anybody out there who hav dovnloaded/saved the pictures from this homepage: http://web.telia.com/~u33227289/saabtemp.html
I will apreciate to recive a copy.
Kind regards
Finn Hansen
[email protected]
 
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