Instruments intermittant...

Post by **rspi** » 13 Apr 2012, 19:58

Ok, I don't know where to go from here. I have tried what I know and can't find answers in the manual.

1. My ambient temp is wacky. I replaced the sensor in the spoiler with another used one and it's still wacky. It will read any temp and sometimes go LO. Today it started at -20 and slowly raised to 73. Then The next time I started it started at 17 and when I looked at it 5 minutes later it was up to 73. I can be driving along and watch it drop to whatever.

2. My car temp gauge is wacky as well. It will rise to 3 O'clock and I'll look down and it'll be at the bottom of the scale like it's 90 degrees instead of 188 degrees. I can watch it go up and down several times while driving. Now the ECU is reading the correct temp like 182 to 215. I have a ScanGauge II hooked up to it and it will stay at 188 to 192 the entire time the car gauge is raising and dropping.

I'm thinking there is some loose ground for the cluster somewhere or something like that. Maybe I have a bad cluster. I don't want to replace the cluster for nothing. I'd like to fix the one I have, the miles are real close to the OBD-I port reading.

I don't like putting 2 problems in one thread because people will answer one and not the other but we'll see what happens.

Post by **erikv11** » 13 Apr 2012, 20:41

Electrical portion of the ignition switch?

Post by **rspi** » 13 Apr 2012, 20:57

I've giggled that around and it didn't seem to help. It's getting worse as well. A few months ago it would only do it every once in a while, now it does it all the time.

Post by **cmblackburn** » 13 Apr 2012, 21:06

rspi wrote:Ok, I don't know where to go from here. I have tried what I know and can't find answers in the manual.

1. My ambient temp is wacky. I replaced the sensor in the spoiler with another used one and it's still wacky. It will read any temp and sometimes go LO. Today it started at -20 and slowly raised to 73. Then The next time I started it started at 17 and when I looked at it 5 minutes later it was up to 73. I can be driving along and watch it drop to whatever.

2. My car temp gauge is wacky as well. It will rise to 3 O'clock and I'll look down and it'll be at the bottom of the scale like it's 90 degrees instead of 188 degrees. I can watch it go up and down several times while driving. Now the ECU is reading the correct temp like 182 to 215. I have a ScanGauge II hooked up to it and it will stay at 188 to 192 the entire time the car gauge is raising and dropping.

I'm thinking there is some loose ground for the cluster somewhere or something like that. Maybe I have a bad cluster. I don't want to replace the cluster for nothing. I'd like to fix the one I have, the miles are real close to the OBD-I port reading.

I don't like putting 2 problems in one thread because people will answer one and not the other but we'll see what happens.

So, I don't know jack crap about Volvo electrical systems (I need to learn!), but on my simple little 1974 BMW 2002, all of the cluster parts ground into 1 big strap. It's known to get corroded after 40 some years on them; and when that happens the gauges all go wacky and twitch like an eye with a hair in it. Simply cleaning the ground helps remedy this problem; and from what I know about basic electronics I'd say that would be a good start point. Only problem... getting the gauge cluster out on a volvo=taking the top of the dash off

on the BMW I can just reach up under the dash and pop it out...

Good luck!

Post by **matthew1** » 13 Apr 2012, 21:44

Age of battery? Terminals clean, and tight?

Post by **rspi** » 14 Apr 2012, 07:19

@ CM: Are you talking about a connector inside the cluster or to the car somewhere?

@ Matt: I have no idea how old the battery is. However, I purchased it used at the beginning of the year (a Volvo battery) and it has good clean connections. I did unplug the coolant temp sensor and the ambient sensor, looked at the connections and made sure they are clean.

Post by **matthew1** » 14 Apr 2012, 10:19

Low voltage can do strange things. Check the battery terminals for secure connections.

Post by **rspi** » 14 Apr 2012, 14:19

When I installed the battery I did make sure I cleaned the post and cable ends real good. I also installed the acid pads and it still looks good and clean. Tight was well.

While driving with me ScanGauge I also monitor the Volts. Usually it's running 13.4. I'm wondering if there is a strap under the dash somewhere that I can check the ground on. I cleaned a couple of ground connections under the hood. I'm thinking about taking the rest of the motor ground straps loose and cleaning those connections and any others that I can find.

Post by **cmblackburn** » 14 Apr 2012, 19:27

rspi wrote:When I installed the battery I did make sure I cleaned the post and cable ends real good. I also installed the acid pads and it still looks good and clean. Tight was well.

While driving with me ScanGauge I also monitor the Volts. Usually it's running 13.4. I'm wondering if there is a strap under the dash somewhere that I can check the ground on. I cleaned a couple of ground connections under the hood. I'm thinking about taking the rest of the motor ground straps loose and cleaning those connections and any others that I can find.

I'd tell you if I remembered if there was one from the cluster (a ground), but it's been a while since I've been that far into the dash. I was at the junkyard today and would have pulled one apart to see, but forgot. Anyone taken one apart recently?

Post by **rspi** » 14 Apr 2012, 20:34

Yes, I have taken two apart lately. They do NOT have a separate ground, just the two connectors behind them. I guess one of the wires in the connectors goes to a ground somewhere. It could be an internal problem in the cluster. I guess I can unplug the cluster and ohm out the ground, they are usually black in Volvo's.