[65madgoat]

Anyone have a photo of where the LITTELFUSE 4 prong Transmission Spark Control / Transmission Controlled Spark relay GM part #3961573 mounts on a 1972 Firebird Trans Am?


Thanks.

[65madgoat]

Anyone with a 1972 on here?

[unruhjonny]

There are several 1972 TA owners here.

This applies quite likely to other non-TA 1972 Pontiacs;

Can you share a picture of the part in question, because as worded, that might be why you haven't had a reply.
(either that or inactivity on the site)

[65madgoat]

TCS 4 prong relay attached.

https://www.firebirdcentral.com/product_p/enc-240.htm

['ol Pinion head]

Am not sure am going to run functional TCS on my '72, not there yet.

might ck with Dave necdb3.

[unruhjonny]

unless i am mistaken, it's mounted on the far side of the dryer housing...

EDIT:
After initially posting, I found it on other cars - but only on AC cars(??).

[65madgoat]

I'll have check as there is a similar relay on the AC box (and still there) and am not sure that then 2 are mounted on it...

[unruhjonny]

I have a small picture library, and looked at all the 1972 Firebirds I had saved pictures of - that's the only spot I could se that style relay at.

['ol Pinion head]

The relay on the pass side of the AC box is the High Speed Blower relay. Have pulled & sold multiple dozens of early AC boxes. For the last 25 years, have typically pieced them together with components from damaged cover boxes, end result beautiful & correct AC box.

['ol Pinion head]

Factory AC cars took a separate harness that was routed out & plugged into the Hi Speed Blower relay & the blower motor.

[65madgoat]

Yes AC wiring to that relay is on hvac box as shown in this thread.

Still have no idea where the TCS relay would be mounted.

[johnta1]

I didn't know the TSC used a relay?

There is a heat switch, vacuum solenoid, and a transmission switch.

There is a relay on the 6 cyl. and chev 307 I think, but on the TA?

There is a horn relay like that though possibly?

[johnta1]

72 Wiring:

[65madgoat]

Thanks. Yeah I have not seen a car (only seen a few stock examples) with one - yet in my parts off the car I have the 4 prong TCS relay shown above.

[unruhjonny]

what's your car's build date?

Maybe it's reflective of a late model year change?

Frankly I wasn't aware of that style part being used on any 70-74 Firebird - and as far as I was aware, typically anything TCS related is mounted to the engine.

I have a 1972 400 here, that I believe is all stock, but know I don't have that relay - and that style is typiclly mounted on a firewall or other flat surface.

[johnta1]

Do you have a horn/seat belt buzzer?

[65madgoat]

Yes to seat belt warning wires. Build date first week of March 1972

['ol Pinion head]

A TCS relay was def not utilized on the '72 455 HO or 400 Birds.
The early & late engine harness thing was a '73 model deal, not in '72.

Page 12H-15, 12H-16, & 12H-18 of the 1972 Firebird Product Description Manual (the blue sheet Assembly Manual from Inline Tube) has great views of the wire harness routing from the temp sending unit (in pass side head) up & through the plastic loop off the valve cover tab, then further up to the TCS solenoid mounted to the rear of pass side of the intake.

[65madgoat]

Super. Thanks for clarifying.