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73-87 Chevy _ GMC Trucks => Interior & Equipment => Instrumentation => Topic started by: Shawn0331 on June 08, 2012, 06:54:36 pm
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Just noticed this yesterday. All gauges except for speedometer have stopped working. My voltmeter is stuck to the left, temp is stuck between 100 and 210, and my fuel gauge is stuck just above 1/4 tank.
Any idea why this might have happened?
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I'd check the big connector on the back of the gauge cluster to see if it's come unhooked. That's what it sounds like to me.
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Blown fuse... Works again.
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Blown fuse... Works again.
:o Wouldn't it be great is life was that simple. ;D
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Blown fuse... Works again.
:o Wouldn't it be great is life was that simple. ;D
It would be...blew the same fuse on the way home last night.
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I'm waiting for the fuse to blow again but it's held up so far today. Any idea where I should start troubleshooting?
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It's the gauge/idle fuse. I see that it runs the gauges, but what's it doing with the idle? It runs just fine with the fuse blown/removed.
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I'd start with checking the plug as mentioned, then the wires for the gauges. Also check the grounds
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I'd start with checking the plug as mentioned, then the wires for the gauges. Also check the grounds
So pull the gauge cluster?
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The 'gauges' fuse may protect multiple ignition circuits, including the 'Ign' taps on the fuse box. Your problem may not be restricted to the I/P and cluster. You might want to start by quickly surveying which appliances don't work with the 'gauges' fuse removed/blown, then install a new fuse and see which of those inop circuits now work.
Tech Tip:
To diagnose shorts without spending a fortune in fuses, take a 10-amp, auto-reset circuit breaker that will fit your fuse box and connect a 12-volt non-polarized alarm module (like a seatbelt warning buzzer) across the blades of the breaker. Replace the blown fuse with the circuit breaker/alarm. Now, every time the circuit shorts, the breaker will open and the alarm will sound... until the breaker resets. It helps save time when your crawling around under the dash, hood, etc. ;)
Before taking the cluster back out, begin by installing the breaker, then reaching up behind the dash and g-e-n-t-l-y nudging the harness to see if you can recreate the problem. Expand your search from there.
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Thanks for the tip. I'll try and get to it tomorrow.
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I haven't had more time to look at it, but after doing a some research (and chatting with my neighbor about it), I think my problems are related to my missing oil pressure sending unit / switch.
Looking at the wiring diagram on Autozone, I found that the oil pressure sending unit is part of the circuit. I already knew that I've been having an issue with the fuel pump running after shutting off the engine sometimes (which also is connected to the oil pressure sending unit).
Hopefully tomorrow I'll have time to check behind the distributor for the tan/white and/or gray wire that is supposed to be connected to the oil pressure sending unit.
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Here's what I found that's making me think this too.
http://www.chevytalk.org/fusionbb/showtopic.php?tid/263217/
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So your saying that you think the wire that is suppose to be hooked up to the oil sending unit is bouncing around and shorting out against something ? Easy way to find out is tape off end and attach wire where it is secured somewhere to see if it stops blowing the fuse. ( I use Bd's suggestion at work all the time, but with resettable mini circuit breakers, saves a ton on fuses ;D).
Or do you think that by not being hooked up at all it is blowing the circuit ?
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I'm thinking it's bouncing around. I remember not finding the switch when I pulled the distributor cap a while back. I did find a bolt in its spot though.
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AFAIK, the oil pressure sender located on top of the engine by the distributor, sends a signal to the oil pressure gauge only. The oil pressure switch that the choke/light runs through (like your link was discussing) is located at the bottom of the engine just above the oil filter.
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I'm not sure, but both are missing on my truck.
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...I already knew that I've been having an issue with the fuel pump running after shutting off the engine sometimes....
This is normal for GM TBI square bodies. Fuel pump afterrun is controlled by the ECM (or in some cases an under-dash fuel module). Some electric pumps will run up to 15 seconds after the ignition is shut off.
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This is normal for GM TBI square bodies. Fuel pump afterrun is controlled by the ECM (or in some cases an under-dash fuel module). Some electric pumps will run up to 15 seconds after the ignition is shut off.
Mine ran for a good 15-20 minutes tonight at my parents house when I stopped by on my way home.
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That's not normal! :o Might have a relay sticking. ??? Next time it happens, check the control circuit for the fuel pump relay mounted on the firewall. Determine whether the relay is being signaled to stay on, or has gone rogue. :-\
See if your neighbor has the fuel/emission manual to go along with that wiring diagram manual he so graciously loaned. 8)
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Update:
I haven't found anything that looks out of whack, but decided to take apart the dash earlier this evening. I found spliced and frayed wires, but I think it's to the fuel selector switch. I only have one tank now and they previous owner bypassed the switch to only use the passenger side tank.
I'll post pics in a bit of what I found under there. While I've got it apart, I bought some new instrument panel bulbs and some chrome paint so I can brighten things up a bit. Saw an article on it and it looked like a good idea. http://www.73-87.com/7387garage/interior/dashlights.htm
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Here's the in-dash wiring I found:
(http://img.tapatalk.com/ae3d8794-c655-22b7.jpg)
(http://img.tapatalk.com/ae3d8794-c664-693b.jpg)
(http://img.tapatalk.com/ae3d8794-c67b-3911.jpg)
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That may change the game. You've got some work ahead of you.... If that's all the PO did, it's not too bad. Hopefully, the rest of the wiring isn't like that. At least, armed with the wiring diagrams, straightening it out is doable.
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My spring retaining clip stuck & I pulled a little too hard on my speedometer. Oops!
Got an entire dash cluster and a brass T fitting for my oil pressure switch and sending unit for $33 though.
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I'm having the exact same problem with my 86 K20 with a 292. My oil pressure sender etc is all in tact and plugged up tho. I just got this truck from my Papaw, who bought it new, but it's been sitting since 06-07. All the gauges aren't working and my CHOKE light stays on all the time. It had the very same fuse blown as well. I haven't had much time to start tracking stuff down tho.
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Fixed! It was a stupid ground I had no idea was loose! After dropping the tank to check for bad wiring from the fuel pimp relay to the fuel pump because my relay was fried, I messed with this ground and it hasn't blown since.
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That grounding point is a common problem in these trucks. Glad you found it.