if you guys have any idea what may be causing this or can steer me in a direction to start at then i would be VERY happy. thank you!

 

i know there must be someone on here that knowsof something to look for to solve the problem..?!

 

Why don't you mention some details like what year/model we are dealing with-it is kinda important... Some symptoms may help too.

 

no particular symptoms it just doesnt work i tried jiggling the ignition, banging on the dash.. are there any other thing you guys can think of.

the car is a 90 740tic auto. im using my tom tom for the speedo right now lol.


devin

 

A good place to start would be checking fuses particularly for the insturment cluster. Then I would remove the cluster carefully and see if one of the electrical connectors may have come loose especially if you made any changes like installing a stereo or something like that.

 

i am actually doing that today. there is a fuse that controls the speedo and tach? ive never heard of that. but when i do my stereo i will pull my speedo. is there anything to watch out for when pulling it?

devin

 

Just take your time and make sure to mark any hoses or connectors you remove with colored tape or masking tape and a sharpie

 

The Volvo instrument clusters are fairly easy to remove, popping the steering wheel off always helps access.
I also tend to think this is a power to the dash problem, speedo and tacho are totally independent systems except for power supply. Both instruments are electronic as well.

Regards, Andrew.

 

ok so everything looked fine during inspection of the cluster. i wiggled wires and everything and got nothing. i have a chance to grad a cluster for 75 bucks. another question is where do you guys in from to hook up your gauges power wise. i went from my radio power and ground and i keep popping fuses but the gauge light will still work. I dont understand but in going to mess with it today and see he i can fix it.

 

I'm going to guess you still haven't checked the fuses? always start cheap before dumping money into something that may not be broken in the first place.. seems kinda fishy to me that both the Electronic Tach and the Electronic Speedo stopped working at the same time.. Poor ground somewhere? or short? Grab that multimeter and start checking for continuity! Get yourself a book.. it's always good to have one for instances such as this! and you might learn a thing or 13!

 

I don't believe the speedo and tach are fused. Does the odometer or trip meter work by any chance? How did this problem begin? Did both quit at the same time? Has the car "always" been like that since you've had it? It's odd that both these gauges are not working as they are not connected other than the fact that they are next to one another. I'd look for some wire breakage, or a circuit board problem.

 

yeah they both stopped working along with the odometer from what the previous owner had told me. i searched the fuses and there was nothing listed for the speedo or tach or gauge clusters. so next step should be pulling the cluster back out and testing the connectors on the back? does anyone know what connections i should check first? thanks guys for all your help. im hoping i can figure this out sooner then later it is almost sticker time and i cant get it done with my gauges not working.

 

There are several plugs in the back of the panel, in additon to some individual grounds, not sure which wires are the ones for the instruments in question. I'd visually check them all, then I'd do some jiggle test with the engine ON to see if the tach comes up. The speedos are notorious for going down but the tachs not so much. If all the wires are intact, check the soldering points and clean and tighten the screws on the circuit board.
Keep posting...

 

im going to go outside in a few and use my test light on the wires and see what i can find.

 

i messed with everything back there and nothing makes a difference. i think i will be buying a new cluster. anyone know what in interchangable?

 

You have my sympathies... I have 940s 1992 / J reg and am still having somewhat similar probs (although my tacho is ok and now the only way I can judge my speed).
First the speedo started to drop to zero occasionally, then more frequently to the point where now it only works maybe once a month
just for a few seconds when the car is first started then nothing after that point.
The trip meter and mileometer now only work sporadically (I bought the car with no handbook and wasn't aware the trip shouldn't be reset while the car was in motion - however, recently, both have been known to clock up 400 miles no probs in one go, perhaps proving no damage done to the digit drums?).
Add to this that if I push the reset button in, the parking brake warning light comes on !!!!!
I have had the instrument cluster out (cleaned the two pin speedo connector) but can see no obvious probs - owing to limited funds, I am not prepared at the mo to take the speedo apart, in order to avoid making things worse.
I have traced the rear sensor wire from the boot well to the first connection box just under the fuel filler tube and all seems to be ok but having no way to jack the car up, I cannot check the actual connection on the back axle at present.
On speaking to a mechanic, he seemed to think it would be the speedo faulty as, were it to be the rear sensor, none of it would work at all - I have my doubts. Surely if the speedo unit were duff, it wouldn't work at all, as opposed to working sporadically?!
Time will tell - service due next week so I will get him to at least visually check the rear connector.

 

OK. so my speedo was the sensor in my rear end. Now i need to figure out the tach issue or if once i do the sensor that has something to do with the tach.

 

have you checked to make sure all your connections are hooked up properly to the primary terminals on the coil? I'm pretty sure all you need to make a tach work is a connection to the coil and to a ground..