Author Topic: Gauges/brights issues help!  (Read 1669 times)

Offline Artezio

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Gauges/brights issues help!
« on: December 09, 2016, 11:29:55 AM »
So I bought an 83 k20 (which I'm not sure is 3/4 ton or 1 ton cause it's a dually) and the truck runs great it has its minor electrical issues though which is expected because of its age and the fuel gauge moves around when you hit a bump or simply because of the vibration of the Diesel engine. It only bounces within a 1/8 tank mark worth of movement, it acts like it's loose so I never know the true fuel level, however it does move as if its reading the level properly and goes to full when I fill 'er up and decreases normally as expected just that bouncing around is all that's wrong with it, also the oil pressure gauge when driving will occasionally read high but a good slap on the dash makes it read normal again but I do not wish to have to slap the dash. Third when using the brights for the headlights hitting bumps will cause them to flicker between normal and brights even on the slightest bump because it's so stiff. Now I bought this truck as my hauler for camping and with the intention of slowly restoring her. And lastly it has an aftermarket cruise control but doesn't work so I don't even know where to begin on that but it's not that important really, any thoughts? Thanks in advance!

Offline hatzie

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Re: Gauges/brights issues help!
« Reply #1 on: December 09, 2016, 12:37:41 PM »
The brights are probably a failing dimmer switch. 
The fuel and oil pressure gauges are probably a loose connection at the printed circuit on the cluster or one of the cluster power or ground splices that can be found several inches down the harness from the cluster plug.
A loose gauge shaft will make the needle swing a bit.  You can get the fuel gauge damped with some special silicone gel or just replace it with a new unit that isn't loose.
SVC & wiring mans --> Here http://tinyurl.com/7387BRD-SVCMAN or My Bucket @ http://tinyurl.com/SQ-SVCMAN
Parts & Illustr Books -->http://tinyurl.com/SqParts
GMSTG Textbooks-->http://tinyurl.com/STG-TEXTBK
Radio Manuals-->http://tinyurl.com/DELCORADSVC

Offline OldGray

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Re: Gauges/brights issues help!
« Reply #2 on: December 09, 2016, 04:39:01 PM »
My Fuel gauge read incorrectly, the voltmeter didn't work so well, and the oil pressure gauge was iffy at best.  One night I pulled off the dash cover and removed each of the gauges on the dash, cleaned all the contacts and added a little electrical grease and put them back in.  This also gave me a chance to replace any burned out dash lights.

Once back together they all started working perfectly.  Well worth the time spent, and not hard at all.
1979 Chevrolet Bonanza / 305 / LWB

Offline 75gmck25

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  • 1975 GMC K25 Camper Special, 350/TH350/NP203
Re: Gauges/brights issues help!
« Reply #3 on: December 16, 2016, 03:56:49 PM »
They sell a spray contact cleaner called DeOxit at Radio Shack and other places.  It works well to clean up corrosion and get better contacts on old terminals.

Bruce