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S10 Blazer weird problem radio, transmission and speedometer all broke

Hello I have an S10 that had A/C issues but the problem is gone until next summer (if I even have it then gas mileage poor)

Anyway, I get in and the radio will not come on-I smack it and the clock part come on then off again. In the past I put 3-1 oil into the power-on switch and instantly it worked again. Too dark and cold to mess with tonight.
I notice the speedometer also is broke then I check wipers-broke also. As I try to get up to speed, the gear seems to want to stay in low (auto tranny) Anyway, I get home and as I shut it off, I hear the radio!, So I put the key to ACC and the radio is just fine Auuugh Too cold too tired tonight so I did not test the speedometer

This is just weird maybe a short? Why would a short effect gears and speedometer?

Help Please

My first guess is a ground is failing. What year model is the Blazer?

The issues may be due to a problem with a power circuit that is common to all of the things you mentioned. The problem is not a short but it is a bad connection that is intermittent. Tapping on suspected trouble spots with a screwdriver handle may show up the faulty area. Check things like the ignition switch, fuse panel, and wire connectors.

Thanks Cougar My Blazer is a 1991 model

Well that next morning, the car ran smooth and has been running smooth since. I see my mechanic on Tuesday because my power window went off its track for the 10th time and Usually I get it up by force but now it is stuck 3/4 closed (plastic window winterizing stuff works well to block the cold)
Anyway, back to my issue. I’ll let him know what was suggested by cougar and see if he can do that without a lot of hours searching out the “bad connection” Bad connection sounds better then “short” So I’ll go with that one. In the meantime, it runs and worse case (well besides shutting down complete) is I’ll have to drive 35 miles and hour until I get it fixed the right way (I’m in dutchess county NY and Route 9 is the main road and that is 40 to 45 most places anyway

Thanks for the help

Glen AKA Da’ Swan

Hopefully the mechanic will have the wiring data to refer to and see how power is provided to those areas you mentioned. I would presume that the power to those areas ties to a common source besides the ignition switch and focus on that area for the trouble. The trouble could be the switch also.

You’re welcome for the help.
Glen AKA Da’ Cougar

Things went well until now. My dashboard light went out and on my way home a trooper pulled me over-seems my tail lights went out as well! So I bang hard on the side of where the light switch is and bam! lights go on again! The trooper give back my lic and reg, and tells me to find a more permenant fix. I suppose it is time to bring it in. Had to be a connection is loose or a short?

Before you do anything remove both side mount battery cables from the the battery.

On the positive cable peel back the red cover to expose the positive battery terminals.

If a lot of corrosion is found on the terminals under the red cover replace the positive battery cable assembly.


Again, the trouble isn’t due to a short. There is either a problem with the light switch or a bad connection after it that ties to the dash lights and the rear running lights. They are usually tied together. The fuse panel is another possibility also. You might be able to find the trouble by moving the wires around that are tied to the switch. Have someone watch the lights while you try to make them go out. Tapping on things with a screwdriver handle can find problems.

Ignition switch. Common problem.