Just Bought A Truck

elliejon · February 22, 2008

Hey all. I just bought a 1988 GMC Sierra 1500. There are a few thngs wrong with it, most of wich I think are connected. The speedometer doesnt work. It's probably the speedometer cable, right? I called the parts stores in the area, and it turns out only 1 could order it, if it's the right size. They said they could order the 31 ", but couldn't get the 49". Is there a way to measure it without taking it out? If I order it, then I can't return it, so I want to make sure I get the right one.

Another problem is the power locks and windows don't work. I have checked all the fuses under the dash, couldn't find any other fuse box. It's a minor problem, but the window is open an inch, and it's COLD here in Maine during the winter.

The gas guage always reads full. The sending unit in the gas tank?

Lastly, the dash lights don't work. Not only that, but when I turn the headlights on, the lights in the radio shut off, as well as the guage showing the temp for the fan. I'm thinking that there's a short somewhere. Maybe it's related to the power locks and windows not working? Or the gas guage not working?

I'm not a skilled mechanic, but I can do most stuff when I have a Chilton's next to me. I just don't know where to start looking. Has anyone else had these problems? Any help would be greatly appreciated!

ColoradoSkiCountry · February 22, 2008

BTT

marko · February 22, 2008

Hello, and welcome to the group.

You have a lot of problems. I think it's best to tackle them one at a time. First and foremost, buy the Haynes manual for the truck. Then read up a bit on the problems you are having.

As for the speedo cable, I wouldn't be so sure that it's the cable. I am not sure if the speedo on an 88 is electronic or cable-actuated. Also, I am thinking you have other problems with the instrument cluster, like the dim lights.

Wiring problems suck. They are all about tracing what is right and wrong. You need a good wiring diagram, and a good multimeter. Start tracing, and let us know how you make out.

As for parts you should be able to get a friendly dealer to let you know what the part number for your speedo cable is. Or maybe one of the more knowlegeable members here should know, if they knew your VIN. Hopefully they read this post and make their expertise available to you.

2017HD · February 22, 2008

Check the tail light fuse for your dashboard lights - I think they were still tied together back then. As for the other stuff - it could either be fuse or wire harnass related - I would look at where the wires run through doors etc for signs of wear and tear - and breaks.