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Unread 01-20-2015, 10:10 PM   #1
topherbarrow
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Join Date: Aug 2010
Location: Tampa, FL
Posts: 25
81 CJ7 Fuel/temp gauge troubleshooting

Hey Guys,

I've been reviewing several threads on troubleshooting the CJ speedo gauges. However, I've been using my test light to troubleshoot and have some awkward results.

When I remove the gauge and clip a direct ground to the negative terminal of the battery, I get the below:

- I terminal, I get power.
- A terminal, I get a solid light.
- S terminal, slightly dim solid light.

The A terminal should blink, right?

When I remove the ground:

- I terminal, I get power.
- A terminal, flashing light.
- S terminal, nothing.

I also get power to the fuel sending unit line. Haven't tested the unit itself as I didn't want to drop tank.

Any thoughts?

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Unread 01-21-2015, 03:37 AM   #2
John Strenk
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1976 CJ5 
 
Join Date: Feb 2005
Location: Shalersville Ohio
Posts: 13,463
Quote:
Originally Posted by topherbarrow View Post
Hey Guys,

I've been reviewing several threads on troubleshooting the CJ speedo gauges. However, I've been using my test light to troubleshoot and have some awkward results.

When I remove the gauge and clip a direct ground to the negative terminal of the battery, I get the below:

- I terminal, I get power.
- A terminal, I get a solid light.
- S terminal, slightly dim solid light.

The A terminal should blink, right?

When I remove the ground:

- I terminal, I get power.
- A terminal, flashing light.
- S terminal, nothing.

I also get power to the fuel sending unit line. Haven't tested the unit itself as I didn't want to drop tank.

Any thoughts?
Did you actually remove the wires from the gauge or the gauge from the speedometer?

If the gauge was connected and the case grounded then you should see "A" Flashing with a test light. "S" should be flashing also but dimmer.

With it flashing in the second case doesn't make sense unless your fuel tank is almost full.

What does he needle do in each case?
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Unread 01-25-2015, 03:06 PM   #3
Willyc
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1982 CJ7 
 
Join Date: Jan 2015
Location: Austin, T
Posts: 3
I just went through weeks of troubleshooting gauges on my 82 CJ7. Oljeep.com has a TSM available for free download and it was great for troubleshooting, Also found a link on the web "Basic Troubleshooting for CJ Gauges" by John Strenk. My problem turned out to be a dead short on the hot lead for all my gauges near the ignition switch. Fried the temp gauge.
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