240DL 86 Instrument Cluster weirdness

[MrPink]

Hi, guys!

New member here. I've searched for this but don't seem to see it, so I thought I would just ask.

My GF has an '86 (and also had an '83 which was just retired due to a collision) 240DL that has developed an odd problem.

About a month ago, she was having trouble with the temperature gauge. It was erratic, sometimes acting normally, other times pegging red and/or moving around. Since it was intermittent, her Volvo wizard couldn't really diagnose the problem. But just in case, we changed out the thermostat in case it was defective.

Well, fast-forward to last night. Last night, while on the freeway, the entire instrument cluster went squiffy. While driving at 70 MPH, the speedometer would pulse at 20 MPH. No gauges. No fuel gauge, no temperature. The clock continued to work, however, and the overdrive light was lit up and would not extinguish. The speedometer would switch between indicating no speed and pulsing at 20 MPH in this condition. The odometer would not advance.

This morning, all is well. I am suspecting some type of component failure (old electrolytic capacitor, bad semiconductor, something along those lines) but really have no idea where to start looking. I am a Japanese car tinkerer and know nothing about these lovely Volvo beauties.

One thing that MAY be related is that I did change out her car stereo in the upper dash location a couple of days ago. However, as much as I do not believe in coincidences, I don't think this is related.

Can anyone suggest some starting point and perhaps what to look for? I am perfectly capable of repair down to component level.

Oh, and one other thing. The clock on her '83 quit working years ago, and her mechanic said it was too much trouble to worry about. What will be involved in repairing her clock on this '86 when it fails?

Thanks for everyone's help!

[billofdurham]

Welcome to Matthew's Volvo Site.

The temperature gauge problem is well known, so the "Volvo wizard" must have been having an off day. IPD, one of our sponsors, have addressed this issue and you can read about it here.

The later problem could well be a bad earth (ground) connection or another documented case, albeit on a 740, was solved by tightening every screw on the back of the instrument cluster. Loss of the dash has also been attributed to a bad electrical portion of the ignition switch. If all goes off again try jiggling the key in the ignition lock.

Bill.

[MrPink]

Hi, Bill:

Thanks for the welcome and the tips. Very interesting on the temp problem, I'll have to take a look at that board and see if I see anything anomalous on it. I see that it's located on/in the instrument cluster. I will also ask her "wizard" about it, as well. I'm a bit surprised that he didn't mention this, as all he does is Volvos and has been her mechanic for over 15 years. I'd yank the board out of the '83, but it appears to be an '86 and later enhancement.

It's funny that you mention the ignition switch. One of the things I had her do as we pulled into the garage (with the cluster AWOL) was shut the car off, and then turn it back on without starting the engine. Dash function did not return, so I think we'll rule out the ignition switch for now.

Not having had this side of her (or ANY Volvo's) dash apart before, how much trouble is pulling that assembly out? Will it be obvious, or will there be some brittle plastic tab I'll miss and bust off trying to take the cluster off? Is it connectorized?

Will I be looking for a single ground wire somewhere, or will it be on the connector?

I will definitely be looking at the screws on the PCB (and the board itself) for the cluster when I get it out.

Oh, I did leave one bit of info out (my bad), and that was mileage. '83 was around 340K, and this '86 is 250K or thereabouts.

Thanks again for the tips and advice! I will report back here with results (and more questions, no doubt).

[MrPink]

Huh- guess new members can't edit posts after a short period of time... I see now that the assembly comes out pretty easily, and I've found the temp board bypass instructions. Cool!

I've also discovered that '86 and later clusters are electronic, whereas the cluster on the '83 is not. Too bad, as I would keep that one as a spare!

I've learned that cold solder is a problem on these, as is also the possibility of the voltage regulator being defective as well. I can't effect any repairs this week (don't have my repair stuff here) but will report back with any progress next time.

[billofdurham]

I really like it when members answer their own questions.

As for editing you should be able to do it using the 'edit' button at the bottom right of the post. There is no qualifying period for this.

The electronic boards are noted for cold solder joints but after 1/4 million miles your joints will probably be going bad. I know mine are.

Bill.