1990 L98 Temp Sender Location
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From: Lubbock, Texas
1990 L98 Temp Sender Location
I'm trying to return a '90 convertible 6speed car to something close to originality and reliability; poor thing has had a succession of boneheads working on it. When I bought it last week the in-dash temp gauge was inop and it had a cheap mechanical gauge rigged to hang under the dash; sensor bulb was in the driver's side head between 5 & 7. I saw a tan wire hanging near there that wasn't connected; tried grounding it and sure enough that pinned the temp gauge, so I bought a sending unit and installed it in place of the mechanical gauge; gauge now works fine. But then in reading through the FSM I see where they're saying it should be a dark green wire. So I looked at my daughter's 90 automatic car, and the sender for it is between 6 & 8...on the opposite side of the engine.
I searched this forum's archives to see what I could find, but nothing useful came up. I did learn that GM changed the sensor layout and control of the cooling fans over the years, so information for an earlier car won't help me much. Not sure about 91. Anyway, can anyone shed any light on this? Is there a difference in the sender location on 6 speed cars, or has mine been pranked with? The tan wire goes into the convoluted plastic loom and looks original, other than being the wrong color and on the wrong side of the car...
I searched this forum's archives to see what I could find, but nothing useful came up. I did learn that GM changed the sensor layout and control of the cooling fans over the years, so information for an earlier car won't help me much. Not sure about 91. Anyway, can anyone shed any light on this? Is there a difference in the sender location on 6 speed cars, or has mine been pranked with? The tan wire goes into the convoluted plastic loom and looks original, other than being the wrong color and on the wrong side of the car...
Race Director
Joined: Apr 2002
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From: Anaheim CA
On my car the dash temperature sender is between #6 and #8. Mine is a green wire.
The temperature switch between #1 and #3 is for the auxiliary fan in front of the A/C condenser.
The dash temperature sender was in the driver's side head on earlier cars. I think up through 1985, but I don't know that for sure.
The temperature switch between #1 and #3 is for the auxiliary fan in front of the A/C condenser.
The dash temperature sender was in the driver's side head on earlier cars. I think up through 1985, but I don't know that for sure.
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From: Lubbock, Texas
Thanks. On '90 models, there is no fan switch. There are two fans, each controlled by the ECM. My daughter's automatic car has the sender between 6 & 8; I'm trying to figure out why mine is between 5 & 7. I'm about to have to pull both heads to replace the gaskets and I want to be sure I'm putting it back correctly. The tan wire has me stumped too. There is a very good possibility mine has been modified. I would especially like to hear from someone with a '90 six speed.
Melting Slicks
Joined: Sep 2008
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From: Cherokee National Forest TN
90 M6 here.
No sender(s) in left head.
Temp gauge sender in right head between 6&8 cyl, green wire.
Primary fan swiitch (temperature trigger) in front of intake manifold below heater hose fitting.
Is it possible that the tan wire you are checking is for the oil temp? Sender is located @ oil filter area. Do not have access to my 8A wireing manual at this writing, if no one responds I will check tonight.
No sender(s) in left head.
Temp gauge sender in right head between 6&8 cyl, green wire.
Primary fan swiitch (temperature trigger) in front of intake manifold below heater hose fitting.
Is it possible that the tan wire you are checking is for the oil temp? Sender is located @ oil filter area. Do not have access to my 8A wireing manual at this writing, if no one responds I will check tonight.
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Thanks, that's the information I needed. I suspected as much; can't think of any reason that a six speed car would have the sender in a different location, but that's the only real difference between my car and my daughter's. I'll be pulling the upper end off in the next few days and I'll try to sort out the wiring harness while I can maybe get to it. The oil temp works, and the tan wire definitely goes to the water temp gauge, but I don't know how it gets there. It's becoming more apparent that it's been modified though.
I really appreciate the response; I needed to know for sure. I've had a lot of Corvettes in years past, and did body off restorations; thought I knew them pretty well. But that was C2's and C3's; this is just my 4th '90 and the first one I had to do much to. Learning as I go...
I really appreciate the response; I needed to know for sure. I've had a lot of Corvettes in years past, and did body off restorations; thought I knew them pretty well. But that was C2's and C3's; this is just my 4th '90 and the first one I had to do much to. Learning as I go...
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Thanks! After your info, I felt sure it had been modified, so I started peeling the tan wire out of the tube and sure enough, it exited behind the brake booster and snakes across the firewall among the other wires and hoses; disappears somewhere behind the distributor where I can't yet see it. But that confirms that it was added as an extension to the green wire that should be connected between 6 & 8. Also, I realized that I erred when I said mine was between 5 & 7; it's between 1 & 3. The passenger side head has the aluminum plug in it with the square indent, so I'm forced to conclude that the heads have been off and were swapped. My gasket set just got here so I'm about to pull the heads; I'll straighten out the wiring while I have it apart. Many thanks for your help!
