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Instruments Off Again, On Again

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J

Jogul

Freshman Member
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In my newly acquired 79 Midget sometimes the gauges are all working and sometimes they are all not working (except the mechanical speedometer which always works). Sometimes when they are not working, if I hit a bump they all come on. Then next time I take the car out they are all off again. Haven't been able to find the problem yet and wondered if anyone could give me a few hints of likely problem spots.

Thanks in advance
Jim
 
Bad grounds.
 
I was hoping since all of them go off and on together there was one common point/connection that was the culprit and hoping someone could tell me where that common point was located.

Jim
 
there is. As I recall, the two grounds are 1. above and to the left of the fusebox and 2. On the inner drivers fenderwall by the rad. I don't believe there are any ground wires under the dash. Also, you might check the engine to frame ground, off the front passenger side of the engine.
 
All of the instruments run off of the same fuse. I would start there. The late model fuse box is oh so very twitchy.
 
Is the fuel gauge also going on and off along with the others? The fuel gauge grounds through the sending unit, like wise an electric oil pressure gauge grounds through the sending unit. If you're loosing both gauges at the same time it's more likely the power source as this is common. I don't have my manual here with me at work, but I don't think the tach is part of the circuit that's controlled through the voltage regulator so I'd look at the fuse block as the next common point. Try removing the wires from the spade connectors on the fuse block one at a time and cleaning the contacts, pop out the fuses one at a time and clean those contacts as well and then see what happens. I think your problems will be gone. As Jack said, bad grounds are notorious in the MGs and should be checked for corrosion and tighness occasionally, but I've also had numerous problems traced to loose connections on the fuse block on several cars. I lost the turn signals, brake lights, and fuel gauge on my Midget on the way back from Spridget 50 and traced the problem to a loose connection off the number 3 fuse. One connection was common to all three problems.
 
That was it! Thanks to all. I was able to get ahold of a wiring diagram and traced the culprit to the second fuse from the firewall. I pulled the fuse and put it back in and all was well. Nice to know how much gas is in the tank now!

Jim
 
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