'98 V70 - Odometer going nuts, gauge issues

[Duffterrall]

Good day everyone!

I am working on fixing the issues I have with my 1998 V70 not starting, and may have caused another problem.
I am uncertain, but I may have had the ignition on when I disconnected and reconnected the battery. The car runs, but the instrument panel is now all janky.

• The speedometer no longer works

• The temp and fuel gauge may not work?

• The clock is gone

• The main odometer reads 0 (I mean, 1 now since I drove it briefly)

• The trip odometer is counting up rapidly even when sitting still

• The "SERVICE" light is blinking and reset does nothing.

Anybody have a clue what happened and how I need to fix it?

I think this video link will show the dash off, with power, and starting.

https://drive.google.com/file/d/1NPndFM ... sp=sharing

[abscate]

That’s not good. It looks like the CDM is fried.

Check that the battery voltage is solid.

[BlackBart]

I need the glossary every time I come to MVS!
https://www.matthewsvolvosite.com/volvo-glossary/

I'm not seeing CDM...... DIM?

[Duffterrall]

Ok, first of all, BlackBart you are the current king of my world for posting that link. Vocabulary has been the bane of learning this stuff.

I had to recheck some of what I as working on, and noticed that there was a loose line. It's a white one that runs from the back of the air intake box around past the throttle and connects to a valve looking place, then to the front near the radiator and fan control circuits.

PXL_20230303_193523671.jpg (405.08 KiB) Viewed 701 times

Comes out of the box above the filter here.

PXL_20230303_193527632.jpg (412.17 KiB) Viewed 701 times

Heads over yonder.

I eventually figured out where it came from, and now I have odometer and clock, and the service light is not blinking. My wife's van is behind me, so I'm not sure if speed is still out, or if that just didn't pickup the short distance I was able to get. Either way, either that affected it or unplugging it and plugging it back in fixed part of the problem. I will follow up about the speedometer.

[scot850]

On these older cars it is a DIM as previously mentioned. I had issues with this and it was after accidentally having the 2 battery leads touch their respective ends of the battery when fitting it causing a spark and after that all hell broke loose everytime we switched the headlights on. Eventually removed the DIM and tried another but it was not compatible with my car. Re-installed the original and all was back to normal. Never understood why this became an issue.

Another thing to check is the B+ cable from the battery to the main fuse box (the kidney shaped one in your first picture just behind the airbox).

Check where the cable enters the fuse box at the front of it. The brass/copper should be bright and shiny. Look below there carefully as they are known to melt and short out the fuse box! 99- are worse for this issue but earlier cars can be affected this way too.

That white pipe you refitted is a vacuum connection to the airbox. Don't believe that had anything to do with your issue.

Neil.

[foggydogg]

Ok, first of all, BlackBart you are the current king of my world for posting that link. Vocabulary has been the bane of learning this stuff.

I had to recheck some of what I as working on, and noticed that there was a loose line. It's a white one that runs from the back of the air intake box around past the throttle and connects to a valve looking place, then to the front near the radiator and fan control circuits.

PXL_20230303_193523671.jpg
Comes out of the box above the filter here.
PXL_20230303_193527632.jpg
Heads over yonder.

I eventually figured out where it came from, and now I have odometer and clock, and the service light is not blinking. My wife's van is behind me, so I'm not sure if speed is still out, or if that just didn't pickup the short distance I was able to get. Either way, either that affected it or unplugging it and plugging it back in fixed part of the problem. I will follow up about the speedometer.

The white tubing is part of the vacuum system, no loose electrons there.
You could try reseating both computer modules - keys in your pocket, negative lead disconnected - but as Dr. Abscate alluded you may have made the instrument cluster unhappy with a stray voltage spike. They don't seem to be very delicate, but they aren't bullet proof either. One chip in the cluster has the odometer number in memory, so since that came back you may have escaped.

[Duffterrall]

Alrighty, I will give that a try. Fortunately I drive this car approximately 24 miles a week, so it can wait. 'ppreciate the insight from both of y'all.

[wizechatmgr]

Try unplugging the battery, put key into position two, plug in battery and tighten clamps. Leave car like this for 2-3 minutes. Start car and check for issue again...

[wizechatmgr]

one part of that white vac hose goes to airbox, then there should be another vac line that goes over to the side where the hot/cold air flap is...

[foggydogg]

Alrighty, I will give that a try. Fortunately I drive this car approximately 24 miles a week, so it can wait. 'ppreciate the insight from both of y'all.

If the cluster still won't cooperate PM me, I have a spare.