84 coolant temp reads lo
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Joined: Aug 2005
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84 coolant temp reads lo
I have an 84 that runs around 200 to 220 (verified with a ratech non contact thermometer) but the guage reads LO. I have verified that the green coolant tmp sender wire has the correct resistance for the engine temp in the bulkhead connector(C100 I believe) Where should I go next? When I first purchased the car a few months ago, the guage worked, but mysteriously seemed to start erronious readings. Now nothing but LO. The switch for the voltage works, as well as the guage itself. Is the processor for converting the resistance to actual reading in the guage cluster?
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Joined: Sep 2000
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From: The Top of Utah
Originally Posted by cdk4219
The switch for the voltage works, as well as the gauge itself. Is the processor for converting the resistance to actual reading in the gauge cluster?
RACE ON!!!
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I was under the assumption that the resistance from the sender needs to be translated to actual digits, from units of resistance, all the way to some sort of voltage so that the numbers on the dash come alive. I have the correct resistance in the bulkhead connector (by the battery) for the temp that the sensor is, and grounding it still reads LO at the guage. I would guess that the processor for translating is in the guage cluster. I should have said coolant temp/ voltage switch the toggle that determines whether the display reads voltage or coolant temp, and I havent determined that the switch works, although when it is switched to coolant LO does show up, and it reads correct voltage.
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Originally Posted by cdk4219
I should have said coolant temp/ voltage switch the toggle that determines whether the display reads voltage or coolant temp, and I havent determined that the switch works, although when it is switched to coolant LO does show up, and it reads correct voltage.
RACE ON!!!
Thread Starter
Intermediate
Joined: Aug 2005
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Yea I'm almost sure the toggle switch works, and I have grounded the wire to the block, and still reads LO Are there som common specific problem areas associated with this circuit? I do have the Helms book and it is very helpful, but I thought there may be a possibility that somebody has had this problem in the past and could be pinpointed. No sense in me taking apart the ever so fragile guage cluster, if the problem is a common terminal connection at the info center or cluster itself. It doesnt seem that many have this problem though.
Pro
Joined: Dec 2002
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From: 84 383 XFire Chandler, AZ
There are tons of issues with the gauge clusters. A couple things to look for are the grounds to the cluster - actually in the whole vehicle. Bad or intermittent grounds can cause funky problems. Also from what I understand GM used a high content tin solder and they have a tendency to break at the solder joint where the pin goes into the pc board. A visual inspection of the cluster may be inorder but it would require removing it to look at it.
