instrument cluster transplant

WanderingOak · #1 11/07/07, 03:18 AM

Well, the speedometer on my '88 Chevy S-10 finally bit the dust. At 318K miles, it was only a matter of time. I've already replaced the transfer case gear and cable, so I know the problem is in the instrument cluster. I do want to get this fixed, just so I won't get any speeding tickets and can pass inspection. Anyhow, I've been looking about for a replacement cluster, and have found a few locally, but they have tachometers in the position where my current one has the fuel gage. Does anybody know if these clusters will fit at all, or would I just be wasting my time unless I had a perfect match? I could just send my current cluster in to get repaired, but that could be expensive and leave me with an undrivable truck while I am waiting.

agmantoo · #2 11/07/07, 06:34 AM

You should be able to find an identical unit on the internet. I would not attempt to substitute as you will only complicate the problem. I would connect a drill motor to the cable and drive the cable and verify that the speedometer works before doing anything. Have you verified the cable is not broken? That would be an easy fix. Does the odometer work?

WanderingOak · #3 11/07/07, 06:50 AM

The speedo works rather intermitantly, never going above 20 MPH, even when I am on the freeway. The speedo and the odometer are in sync, though, so when one goes out, so does the other. Also, the Vehicle Speed Sensor in the back of the speedometer keeps giving me a SES light. Unfortunately, I'm working by myself, so unless I completely remove the cable, it would be difficult for me to check everything with a drill.

agmantoo · #4 11/07/07, 02:07 PM

Access the instrument panel back side. The cable should come out but pulling on the end. Sounds to me as if the cable is broken and the broken ends are catching on each other thus driving the speedo sometimes. At above 20 MPH the cable could be turning to fast for the ends to catch each other.

WanderingOak · #5 11/07/07, 03:47 PM

I thought about that. However, the cable and gear were put in new in January 2006. The speedometer had been flaky for the past 6 years, so I decided to replace them first. The speedometer worked for a while, then almost completely quit ten months later, and it's been that way ever since. The cable was almost completely worn through at the gear end when I replaced it, so it could be that there is something wrong with the transfer case that's destroying cables. Then again, the bad cable was extremely loose (not even finger tight) when I removed it, so perhaps that is what destroyed it. I checked the cable this afternoon, and it is on tight. Right now, the truck is all I have to drive, so I'm going to wait until my car is out of the shop before I attempt any repairs.

cfabe · #6 11/07/07, 03:54 PM

The gauge with a tach will fit physically, but you would need to re-pin the electrical connector because some of the wires are in different locations, also some of the gauges won't work properly because you don't have the proper sending units in your engine. If you want to pursue this PM me and I can get you the wiring diagrams.

WanderingOak · #7 11/08/07, 05:46 AM

Quote:

Originally Posted by cfabe

The gauge with a tach will fit physically, but you would need to re-pin the electrical connector because some of the wires are in different locations, also some of the gauges won't work properly because you don't have the proper sending units in your engine. If you want to pursue this PM me and I can get you the wiring diagrams.

I was afraid of that. The local gauge sets costs about $40.00, while I've found the right one online for $80.00, including shipping. I'd rather just get the right gauge set than have a kluge job behind my dashboard. Thanks for the offer though.

foxtrapper · #8 11/08/07, 08:13 AM

I don't know your S10 specifically, but typically, the wiring harness installed in the production line is the same for all models and trim packages. This makes it much easier for the factory to install the upgrades and premium packages.

As such, you can typically install the fancier dashboard simply by taking the old one out, and dropping the new one in. I've done it myself on a number of vehicles.

cfabe · #9 11/08/07, 10:25 AM

fox,
I checked the wiring diagrams. On the s-10 they did change the pinout. Also, the vehicles with "idiot light" clusters got difference sending units on the engine than the ones with gauges. Oil pres, Water temp, etc.

WanderingOak · #10 11/14/07, 07:35 AM

Well, I still haven't found the right cluster. Since I do get the SES light when the speedo isn't working, I am starting to think that it might be the gear that went bad. The speedometer has never been completely accurate, and the gear has been replaced twice since I have had the truck. From what I understand there are several different speedometer gears that are available for my truck. Each time the gear is replaced, the new gear is exactly the same type that it was before. If the wrong gear is used, will it eventually self-destruct? The truck has original wheels and standard tires, and I don't think anybody has put any oddball gear ratios in the truck, so the dealership should be able to figure out what the original gear was through the VIN or 'build sheet', shouldn't they?

agmantoo · #11 11/14/07, 09:33 AM

You would think a dealer could figure is out but I had a tractor that kept blowing head gaskets and the replacement gasket was always as the original. With a chance look into the dealers parts books I saw that was a serial number break. Early versions had a part number the same as the gasket I had and the numbers above a certain point had another part number for the gasket. Once this was brought to their attention the problem disappeared. The tractor was bought used by me and the previous owner had the same problem. I figured that is why it was traded initially as they could not get it fixed. The tractor has performed admirable since. You need to have the vin number researched and the parts that exist compared to ascertain you have the correct setup.

cfabe · #12 11/14/07, 02:22 PM

The speedo gears are a matched set, I guess it's possible you've got a mismatched set in there that doesn't mesh properly. The dealership should be able to get you the right gears.

WanderingOak · #13 11/16/07, 05:28 AM

The way the truck is behaving now, I am thinking that it might in fact be the cable. The other day, the speedometer sat flat most of the day, then I heard something 'snap' up by the firewall, and then the speedometer needle began jumping about like a frog leg hooked up to a battery. After that, the needle has been pretty much dead, only jumping about occasionally. Of course, unless the needle is moving, the SES light is on. So, what could cause a speedometer cable to go wonky with less than two years use? It was a new cable, purchased from the dealership.