Temperature sending unit has three wire's

[Mike71lemans]

Looking for info on my 71 Pontiac lemans sport. 350 engine the temperature sending unit has three prongs on the top. All I can find is a sending unit with eather two terminals or one. The sending unit is in the intake by the thermostat.

 

[melsg5]

found this on another site from 2005

That is the transmission controlled spark coolant temp switch. The "TCS" system controlled the vacuum advance through a solenoid mounted towards the rear of the intake manifold - for emission control purposes. The solenoid in turn was switch on or off depending upon vehicle speed (TH350 and TH400 equipped cars) or gear selection (3 or 4 speed manual transmission equipped cars). The switch you have was an override to allow vacuum advance under all conditions only when the coolant temperature was well above normal.

GM part number is 6490384 and the AC-Delco part number is G1868. Both are long discontinued and no aftermarket parts were ever available. If you still want one for (resto purposes) keep an eye on e-bay.

 

[Mike71lemans]

Ok thanks for the info. Not really looking for resto sending unit is bad and want to replace it I'll just get a single prong sending unit a d make it work

 

[melsg5]

that should be easy, i assume two of the wires go to the solenoid, eliminate them, and the third goes to the temperature light.

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[cammerjeff]

I may have still have a used one in my stash, but I would have to search for it, I parted a few 70's out years ago and kept those 3 pin temp senders for spares, but no longer own a 70 GTO so I don't need them anymore. If you are interested I will look later this week.

 

[G-210406]

I may have still have a used one in my stash, but I would have to search for it, I parted a few 70's out years ago and kept those 3 pin temp senders for spares, but no longer own a 70 GTO so I don't need them anymore. If you are interested I will look later this week.

How much do you want for one, I would be interested in one.

 

[phil d]

i would be very interested in those switches/ sending units.

My phone is 908.208.7778

Phil

I may have still have a used one in my stash, but I would have to search for it, I parted a few 70's out years ago and kept those 3 pin temp senders for spares, but no longer own a 70 GTO so I don't need them anymore. If you are interested I will look later this week.

 

[cammerjeff]

So far I have not found one in my unorginized storage, but if I find one I will post it here.

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[G-752551]

Looking for info on my 71 Pontiac lemans sport. 350 engine the temperature sending unit has three prongs on the top. All I can find is a sending unit with eather two terminals or one. The sending unit is in the intake by the thermostat.

Did you find this ? My 72 lemans 350 has three male prong plug in for the temp sensor. I can’t find one at all

 

[melsg5]

Did you find this ? My 72 lemans 350 has three male prong plug in for the temp sensor. I can’t find one at all

You need the TCS solenoid to work or just want the temperature function?