Fuse panel issue

[Rambo2]

Hello all,

I'm still getting accustomed to this amazing site, so please bear with me as I explain the issue I am having with my 1970 GMC C15.

The instrument panel fuse keeps blowing leaving me with no dash lights, tail lights, or fuel gauge (not sure if that is part of the same problem or not). I replaced the headlight switch several months back and have finally gotten a chance to spend some time on it. Also, the battery seems to die pretty quickly if I put the key into the accessory position. If I don't leave the key in accessory, it turns right over and maintains a charge. Again, don't know if this is related or not.

I have a custom stereo in it, but don't see any issue with the wiring there since it was hooked up long before the issue came up and still works when the battery is engaged. The fuse box under the steering column looks to have been altered and the years. I am good at wiring stereos, but fuse panels and accessories going to them are a little out of my comfort zone. I would like to fix it myself, but wonder if I should take it to my local repair shop to be safe.

Any ideas? Any help wild be appreciated. Thanks!

[dmjlambert]

You may have a short. The first thing I would do is remove the connector to the instrument cluster and see if the fuse blows with it disconnected. If it does not blow the fuse any more, the problem may be in the instrument cluster. If the fuse blows even with the cluster connector removed, the problem is not in the cluster.

If you find it is the instrument cluster, remove the cluster and visually inspect it carefully, you can also test the traces with an ohm meter to check for shorts to ground (bare metal of the instrument cluster). Removing the cluster is not too hard. You just unscrew the speedometer cable and oil gauge tube, putting a catch pan under the tube, and remove the screws holding the panel on, and remove the knobs and nuts that hold the panel on, then maneuver it around to remove it. Some people find they need to loosen and slightly lower the steering column, but on my truck I don't need to do that.

Post pictures and ask questions here to get some help.

[Rambo2]

Thanks for the info. I will try and get some pictures of the fuse box. I was wondering about removing the cluster and more specifically the oil gauge tube. Do I remove the oil gauge tube on the back of the cluster or under the hood?

Thanks.

[dmjlambert]

Unscrew it from the back of the cluster. I use a small wrench from my ignition wrench set. The most proper tool is probably a small flare nut wrench. It will probably drip a very small amount of oil. If you start the engine with it disconnected it will stream oil out of it. I have moved my truck over a couple of parking spaces with the cluster disconnected, and I catch the oil in a pan when I do that.

[dmjlambert]

This is the nut to unscrew