Identifying 850 instrument cluster? (Intermittent no gauge and trip computer reset issues)

Post by **Chuck W** » 12 Jul 2020, 22:05

We've been having an issue with the trip computer, and now the instrument cluster not working or resetting over the past few months.

First it was the trip computer resetting when she would go to start the car. It wouldn't do it every time, but enough to be annoying.

Recently, I replaced the ignition switch (Volvo) and thought the problem had cleared up.
Wrong. The trip computer will still occasionally reset itself, and now it's taken to having no gauges or indicators after you start it. The car runs fine, but nothing works. You stop and restart, and you're all good.

We replaced the cluster(VDO) with a boost gauge cluster ('97 GLTs had no boost gauge) not long after we bought the car 4 years ago. Swapped the ODO and went on our way.

The trip computer started its resetting thing about a year ago, and the gauges is withing the past couple months.

They don't reset/die when running, only during start up.

I have another cluster in the garage, but I don't know what year it's out of. Pretty sure we need a 96-97 for her car. The only PN I have found is 9434076, which is not for a cluster, but one of the sub-components, it looks like.

Is there any other way to tell what year it's out of?

Post by **Chuck W** » 14 Jul 2020, 14:29

Any way to Identify the clusters?

Post by **Clemens** » 14 Jul 2020, 14:54

Chuck, post a photo of the cluster you have. this should help identify it.

Post by **Chuck W** » 14 Jul 2020, 16:11

Clemens wrote: ↑14 Jul 2020, 14:54 Chuck, post a photo of the cluster you have. this should help identify it.

So, it looks pretty much like all of the clusters I've seen.

I *think* I've only pulled clusters from '96-'97 cars, but i can't remember.

Post by **erikv11** » 14 Jul 2020, 18:48

Short answer is I don't know about the part numbers and year.

But I don't think the year matters, it will work since you are doing VDO > VDO. I'd try it out without swapping over the odo, if it works then take the time for that too.

Post by **scot850** » 14 Jul 2020, 19:44

One thing I learned was NOT to press the trip meter to reset while the car is moving. This will eventually break the gear teeth.

Volvo used 2 suppliers. VDO and I think the other was something like Yakima? I think those Yakima were only used in earlier years.

Neil.

Post by **erikv11** » 14 Jul 2020, 19:57

Yazaki

Post by **Chuck W** » 14 Jul 2020, 21:04

Yeah, I did some digging around before I posted here, and didn't find anything definitive on PN's or any clues to a MY for cluster.

I did find that the early cars pulled the speedo signal from the gearbox and the later ones from the ABS. Late cluster-->early car works if you tap into one the ABS sensor signal. No info on early cluster--->late car, however.

Ozark Lee posted this here a while back.

There is a difference in the speed sensor setup between the early and late models. The early models with the speed sensor on the transaxle have a sine wave output. The later models have the square wave pulse train that is generated by the ABS wheel sensors and, after being routed through the ABS module, it feeds the cluster. Both systems use the same frequency / axle revolution.

Using a newer cluster in an older car is pretty easy, just tap a wheel sensor and you then have the square wave that the cluster wants to see. Using an older cluster on a newer car falls into the "I don't know" category since I don't know how the circuit actually works. If it is just counting pulses once they get over a voltage threshold then it really won't care what form the signal comes in as and an older cluster should work fine. If I were designing that circuit that circuit I would use a comparator with a mid point threshold on the sine wave to essentially convert that sine wave into a digital signal but I didn't design the circuit and I've never tried using an older cluster on a newer car.

Her current cluster works great, and the odo is even original and still working. It just appears that we have a bad power connection issue on the CB perhaps. (A guess, from looking at wiring diagrams).

About all I can really do is swap out clusters and see if things work, I guess.

Post by **misha** » 15 Jul 2020, 16:39

In what shape is a battery?
If it doesn't have required capacity(not just voltage,but amps)it will reset the board computer while cranking.
So....it could be weak battery,positive and negative battery cables that have high resistance or bad ground.
Time for digital multimeter readouts.

About instrument cluster production date...every cluster have a little table with month and year of manufacture....including the one in the picture.
They are not the same....they divide on '92-'95 and '96-'97...because of speedometer signal changes.
Yazaki is visually different than VDO and not compatible with it,so they are not interchangeable.
The one from the picture is VDO.

Post by **Chuck W** » 15 Jul 2020, 20:56

The trip computer will reset itself when the key is just turned to the "ON/RUN" position, just before going to start/crank. We haven't watched to see if the cluster issue happens then, as it's only happened a couple times now.

The battery, etc appear to be in good shape, but it might be worth a check on the cables.

Looking more closely at the spare cluster, it does appear to be a '95 unit. Based on Ozark Lee's post I quoted above, it might be worth trying to see if the speedo recognizes the input.