Hi, I bought a 1998 Volvo s70 and I’m having issues with the instrument cluster. When I start it up in the morning everything works fine. After sitting in the sun I’ve noticed none of my gauges work. My drive home is 15mins and within that time they will start bouncing everywhere and then eventually start working again. Any ideas of what’s wrong or where to start?

 

It definitely seems heat related, I just started the car up after it sat in the shade for a while and it works fine.

 

Check all the grounding points for the instrument cluster and make sure they are clean and tight. Other than that it may be a cracked solder joint on a printed circuit board that is heating up and separating, then contracting and making contact again when it cools down. Check the attached wiring diagram. It is for an 850 but I have used it on our 98 S70 and found the wiring is the same (so far).

 

The cluster is unfortunately a computer module that communicates with the PCM and the TCM to operate. The gauges are "fake" if you can use that term. The test process for the warning lights is turned on and off by voltage as you might have noticed if you notice things like that. So it's likely you've got a little bit of bad solder joint in there somewhere. it could be something simpler, like an intermittent loss of power due to some corrosion that you could see and find and address, but there's no guessing that on the internet. You could consider finding one in a junkyard and see how that goes. That would work on a 98. They are normally pretty reliable.

 

I've removed and opened the cluster on 850s a few times to replace odometer gears. I'd assume the 98 S70s are the same. (there should be some vids on Youtube on how to remove the cluster - but its as simple as removing 7 or 8 screws (one's hiding in the vent, a couple where you need to drop down the steering column, and over by the glove box. Once out you can prop up the driver's corner of the dash to access the cluster. Once the cluster is out, you can check the connectors/cables on the back, then open up the cluster (as I recall there's about a dozen or so Torx #8 screws) where you can inspect the circuit board, ribbon cable connections etc. You should be able to also swap in one from another car as noted. Clean up what you can and see if that helps or simply leave the replacement in.

 

Thanks guys. I got rained out today but I’m going to check this stuff tomorrow. When(or if) I find the problem, I’ll update on here what it is to help the next person.