Temp gauge quit working
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Joined: Aug 2011
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From: S. Daytona Florida
Temp gauge quit working
Hello again,
Just got my car back from the transmission shop and noticed the temp gauge quit. The wire coming from the temp sensor (LH Head) has broken and pulled out of the harness. My question is where does this wire go so I know which loom to look into? I have a FSM but can not find the wiring diagram for the gauges. Thanks, Kim
Just got my car back from the transmission shop and noticed the temp gauge quit. The wire coming from the temp sensor (LH Head) has broken and pulled out of the harness. My question is where does this wire go so I know which loom to look into? I have a FSM but can not find the wiring diagram for the gauges. Thanks, Kim
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Joined: Aug 2011
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From: S. Daytona Florida
Hello again,
As an update, I removed the battery checked the harness's under the master cylinder going into the car, no broken black wires. Iam thinking the wire is in the harness by the distributor behind the LH valve cover, yes the one very difficult to even see not less splice another wire into. Please someone tell me it is not in there! I just replaced the heater core a few weeks ago, I don't need another PITA job. Looks like an aftermarket gauge might be in order, LOL. Kim
As an update, I removed the battery checked the harness's under the master cylinder going into the car, no broken black wires. Iam thinking the wire is in the harness by the distributor behind the LH valve cover, yes the one very difficult to even see not less splice another wire into. Please someone tell me it is not in there! I just replaced the heater core a few weeks ago, I don't need another PITA job. Looks like an aftermarket gauge might be in order, LOL. Kim
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Hello again,
Just got my car back from the transmission shop and noticed the temp gauge quit. The wire coming from the temp sensor (LH Head) has broken and pulled out of the harness. My question is where does this wire go so I know which loom to look into? I have a FSM but can not find the wiring diagram for the gauges. Thanks, Kim
Just got my car back from the transmission shop and noticed the temp gauge quit. The wire coming from the temp sensor (LH Head) has broken and pulled out of the harness. My question is where does this wire go so I know which loom to look into? I have a FSM but can not find the wiring diagram for the gauges. Thanks, Kim
What yr is this?
Many look at the sensor under the valve cover driver side and assume thats the temp sensor...actually there are at least 3. Four counting the cold start switch/sensor. No....5 if you have the ERG timer/temp switch.
There is 1 for the ECM mounted in the front of the intake. Another for the aux fans, driver side between #1 & 3 cyl. The sender for the gauge is the one on the passenger side head by #6 & 8 cyl. BY the dipstick.
The wire is pretty easy too....its a single wire sleeve that exits the Harness trunk under the wiper motor and runs around behind the dist with the EGR timer switch wire and a vac line. Pulling the dist is easy enough to get better access. I would not advise wrestling the harness much...these are famous for internal rot so the first time after 20 yrs that a section gets moved it breaks inside the insulation. So yeah, trans work could easily have broken that wire or damaged it. Make them fix it actually...
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From: S. Daytona Florida
Leesvet,
Thanks so much. I have a 91 L98, I have the FSM but only one book, the big red one. I figured the wire was in the harness by the distributor, as the oil pressure switches are there also. I have no sensor like everyone says I do on the passenger side between the last two plugs. My temp gauge sensor is on the drivers side between the first two plugs. My fans are controlled by the ecm, however I have a switch mounted on a tee where the gauge sensor is to bring the fans on much earlier. Anyway thanks so much. Looks like I am going to pull the distributor today. I wopuld have the shop repair it they are 20 miles awqay, and I can fix it in a lot less time. Kim
Thanks so much. I have a 91 L98, I have the FSM but only one book, the big red one. I figured the wire was in the harness by the distributor, as the oil pressure switches are there also. I have no sensor like everyone says I do on the passenger side between the last two plugs. My temp gauge sensor is on the drivers side between the first two plugs. My fans are controlled by the ecm, however I have a switch mounted on a tee where the gauge sensor is to bring the fans on much earlier. Anyway thanks so much. Looks like I am going to pull the distributor today. I wopuld have the shop repair it they are 20 miles awqay, and I can fix it in a lot less time. Kim
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Maybe the heads have been off ,replaced on opposite sides and they were too lazy to remove the blank plug to fit sender in correct position on pass side.
Wire for temp gauge is in the small harness that runs down to starter motor/ knock sensor.
Originally the wire came up from starter behind exh manifold to temp sender
If your gauge was working then the stock wire must have been extended to the new position.
Find the dark green wire in the harness by the starter ( or trace back up that harness to main harness on firewall until you find it )
Last edited by vetteoz; Dec 23, 2011 at 08:06 AM.
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If the "T" were a good idea GM would have used that to simplify the system and localize all the senders. There is reason why they are different places...the gauge wants to she the hottest water from a head, so does the switch for the aux fan but it is not working all the time, rarely actually. The ECM needs to see an avg temp exiting the intake going toward cooling.
Just layout the wire, place it in insulating conduit or spiral sleeve and put the correct sensors in the correct locations. Do NOT mix them up as 1 is only a on/off switch and the others are variable range sensors.
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From: S. Daytona Florida
Leesvet,Vetteoz,
Vetteoz, You nailed it! Obviously the heads were off (who knows what else) and the PO decided to put the left on the right and vice versa. I do not understand how this happens, but it does at my work also all the time. I really wonder some times. Why not put it back together like it came apart. Anyway I found the dark green wire hanging loose by the starter, and yes someone extended the wire. I spliced another wire routed it the sensor and all is fine. I did try to get the plug out to put the aftermarket fan switch there but could not, even snapped off a ground down 3/8 extension. Thats why I installed the tee. Now the gauge and fan switch share the same water. All normal fan functions from the ECM still work, (fans on when a/c comp is on). For now I am set, thanks to you both, and at a later time I will try and find some 5/16th bar stock to remove the plug and yes install the gauge sensor there where Chevy wanted it, and leave the fan switch on the left head. Thanks again for all the help. Kim
Vetteoz, You nailed it! Obviously the heads were off (who knows what else) and the PO decided to put the left on the right and vice versa. I do not understand how this happens, but it does at my work also all the time. I really wonder some times. Why not put it back together like it came apart. Anyway I found the dark green wire hanging loose by the starter, and yes someone extended the wire. I spliced another wire routed it the sensor and all is fine. I did try to get the plug out to put the aftermarket fan switch there but could not, even snapped off a ground down 3/8 extension. Thats why I installed the tee. Now the gauge and fan switch share the same water. All normal fan functions from the ECM still work, (fans on when a/c comp is on). For now I am set, thanks to you both, and at a later time I will try and find some 5/16th bar stock to remove the plug and yes install the gauge sensor there where Chevy wanted it, and leave the fan switch on the left head. Thanks again for all the help. Kim
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