[71pp'sGP]

Ok guys, just had my engine rebuilt on my 71 Grand Prix the car is a beast......one problem the guy who built the engine at enginelaboftampa.com told me my temp sending unit wasn't working properly so I'm needing to change it out......its the 3 prong unit, I've looked from one end of this country to the other and can't find a 3 prong sending switch anywhere. I've found 2 prong temp sending units will they work?......is there any other alternative I was told to put me a after market temp gauge. But I really want to keep the car as original as possible. Thanks. Pic coming soon

[77 Canamman]

See this thread:

http://forums.maxperformanceinc.com/...ght=prong+unit

The three prong switch is solely used for the Transmission Controlled Spark emission control system. The temp sending unit is located on the intake manifold on a 1971 model.

[428ho4spd]

Unfortunately, a known good used or NOS part is the only choice.

[71pp'sGP]

on my engine i dont see a temp sending unit on the engine head, the only one a have is on the intake its a 3 prong

[71pp'sGP]

Originally Posted by 428ho4spd

Unfortunately, a known good used or NOS part is the only choice.

will a 2 prong sending unit work,

[david400]

I believe that plug you have there is the TSC control plug . you dont need it at this point IMO. you need the single termanal plug for the heat gauge ,should be a single green wire there for the heat gauge plug .

[428ho4spd]

Originally Posted by 71pp'sGP

will a 2 prong sending unit work,

Actually, a '69 style single prong switch will work fine if your not using the TCS system.

[428ho4spd]

Originally Posted by david400

I believe that plug you have there is the TSC control plug . you dont need it at this point IMO. you need the single termanal plug for the heat gauge ,should be a single green wire there for the heat gauge plug .

This plug actually does both, TCS and temp switch for cars with standard gauges (idiot lamps). Rally gauge cars had another separate sending unit on the opposite side of the intake for the gauge temp.

[david400]

Ahhh, I see ,Thank you Grant