the coolent temp gauge on my 86 fire bird refuses to work.
here is what I have tried/know:

there is power to the gauge, when I turn the ignition on the niddle jumps. but I not sure if it is sappose to do that since none of my other gauges do that. does you temp gauge move when you start your car?

I have checked the cercit board on the back of the gauge cluster its fine.

I have replaced the gauge Coolent temp sending unit.

I have replaced the gauge.

I have followed the Two wires that come out of the sending unit. the two wires join in to one by the blower moter.

I have followed that wire all the way to inside the passenger side kick pannel. it is a tanish colored wire. and if I remember right the wire going to the gauge is green i think. (there isn't a tan wire to the temp gauge)

is there some kind of relay or some thing between that wire and the gauge?

the gauge coolent temp sending unit is not even in the wiring diagrams I have.

I need to get this fixed.

If it was working I would not have a junked engine that over heated I would have know that some thing was wrong

thank you very much

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Chuck
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I'm not shy, I just
observing my prey.

 

did the gauge ever work since you got the car? Where is the temp sending unit located? Also I dont understand why two wires connect to one. that doesnt make sense. Also I think there are 2 sending units for temp. One for the ECM the other for your gauge.

 

Chuck,

Your dash instrument sounds as if it is functioning correctly. The indicating needle should move to the extreme high position when you crank the engine. I've never found out why GM decided to do this with the coolant temperature gauge, or if it is just a quirk of the system, but they ALL do it - from my '84 Fiero to the wife's 2000 Astro van.

What model '86 do you have? The TPI engines use more than one sensor (actually, three). The carbed engines have also have three sensors, one for the ECM, one for the gauge, and one for the electric fan. The wiring harnesses are slightly different for each model.

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Later,
Vader
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"I'm'a do Things My Way - It's My way or the Highway."
Adobe Acrobat Reader

 

Yeah, I'm thinking you did the wrong one. The one for the gauge is on the driver's side between #1 and #3 cylinders.
Although you said it was a green wire, so it doesn't sound like the wrong one...

 

2-wire sending units are for idiot lights, 1 wire for hot, 1 wire for cold. You need sender with 'button' on top that takes green female spade connector with black cover with slot cut into it. that is why you are not getting anything!

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1957 3/4 rat
1966 c10 panel
1968 c20 350, 350
1982 camaro 305, THM-200-R4
1984 Monte Carlo, 350, th-350
Everett, WA

 

the gauge has never worked
the sending unit is right next to the one for the ECM, driver side of the plenum.

------------------
Chuck
-------------------
I'm not shy, I just
observing my prey.

don't forget the Firebird is an F-Body TOO

 

I have the MPFI (TPI)
the one for the ECM has two wires -yellow and black, that is shown in my wiring diagram.
the one for the fan in down by the manafolds.
the one for the gauge has two wires going to it, dark purple and brown.


------------------
Chuck
-------------------
I'm not shy, I just
observing my prey.

don't forget the Firebird is an F-Body TOO

 

It may have been the wrong wire I followed, I'm pulling out my engine this weekend to rebuild it. It should be easyer to get to the wires with the engine out.

------------------
Chuck
-------------------
I'm not shy, I just
observing my prey.

don't forget the Firebird is an F-Body TOO

 

the plug is green and the sender has the two spade conectors. it has a wire bent like a C that holds the plug on.

------------------
Chuck
-------------------
I'm not shy, I just
observing my prey.

don't forget the Firebird is an F-Body TOO

 

I just remembered some thing!
I put Teflon on the threads of the sending unit. does that need a ground with the two wires? Maybe thats why they join into one?

Thank you for helping me out.


------------------
Chuck
-------------------
I'm not shy, I just
observing my prey.

don't forget the Firebird is an F-Body TOO

 

Chuck,

Plug a 100 ohm resistor in place of the sensor, and the gauge should go to almost 240°F. If the gauge doesn't move, try bridging the resistor at teh foil traces at the rear of the instrument cluster. If it doesn't work there, the gauge is toast.

------------------
Later,
Vader
------------------
"What a Day..."
Adobe Acrobat Reader

 

I still say you have the wrong sending unit. My 82 camaro, 84 monte carlo that came with factory guages both had button top senders, my 67 had 2 wires, for 'cold' and 'hot' idiot lights, but Vader is right on as far as the guage goes...

 

The temperature sending unit that you are describing sounds like the cold start injector temperature switch. It has a purple and a tan wire going to it & is next to the ECM temperature sender at the front of the intake manifold on VIN F & 8 motors. The temperature gauge sender is located on the driver's side cylinder head, between cylinders 1 & 3.

The temp gauge goes to full scale during start because the "bulb test" feature grounds the gauge input. With an indicators cluster the temp bulb lights during start & with the gauges cluster the gauge goes to full scale during start to verify operation.

Tim

 

I found what you are talking about.
there are two sensor looking things in that area, a one wire unit and a two wire unit.
I would think that the two wire one is it. I noticed that the wires go behind the exaust pipes and that they are loose when I moved them I notice that some of the black covering is melted! the retainer must have broke.
ofcourse it started raining right when I found that out so I will check it out tomarrow. I sure thats where the problem is.

Thanks!

------------------
Chuck
-------------------
I'm not shy, I just
observing my prey.

don't forget the Firebird is an F-Body TOO