Relay's on 1972

[Calvin C.]

I am going thru my dash on my 1972. I have come across a relay that is bolted to the body behind the dash, it has I believe a tan, yellow, blue and black wire. It may be a tcs relay. What is it and how can I get a replacement.

thanks

cal

[george romano]

Re: Relay's on 1972

Thats the delay relay for the TCS system. I believe the same relay is used under the lower shift console to control the seatbelt warning light/buzzer on those models so equipped.
The colors you noted are correct.

George

[Geoff C.]

Re: Relay's on 1972

Hi Cal

If the colors match these and the connector looks like this, then that is the TCS relay. It will be difficult to find new, since it is discontinued. It may fit other Chevrolet car lines in 1972, although that is just another avenue to explore.

Neither the early 72 with the seat belt timer, or the later with the seat belt buzzer and seat belt relay have any circuits in common with the TCS circuit, except they both draw on a 12 volt battery.

Geoffrey Coenen

[Calvin C.]

Re: Relay's on 1972

What does it do and what problems will I have if I do not repace it.

cal

[Jack H.]

Re: Relay's on 1972

TCS= Transmission Controlled Spark. Essentially, it's part of the car's emission system.

The 'smart' relay fires the solenoid mounted on the carb to raise/lower engine idle RPM based on several inputs (has the engine just been started, what's the coolant temp, what gear are we operating in) to 'optimize' tailpipe emissions.

MANY original and subsequent 'Bubba' owners removed and discarded the carb mounted TCS solenoid and its partner, the distributor vac advance solenoid, thinking they were recovering performance lost during the engine changes made in the early 70's to comply with Federal emissions mandates...