72 LT1 TCS relay

[Rob C.]

Cound some one tell me how to test the relay. I need to no if it works. I put in a trany TCS swich and nothing.
I put in a solinoid and nothing eather. So before I go out and try to find a new one I need to test the one in my car. Then if that is ok then start to pull my hair out.
Thank You,
Rob

[Alan S.]

Re: 72 LT1 TCS relay

Hi Rob,
I noticed no replies yet. I know there's a schematic with a description and test procedure for the 71 CEC system in the Chassis Service Manual. Have you checked the 72 Manual for any help with your TCS?
Regards,
Alan

[William C.]

Re: 72 LT1 TCS relay

In addition to the info in the service manual, you might want to check the trans switch to see it it is actually functioning. The switch at the trans (assuming manual trans) depends on a flat spot on the shaft to detect the gear selected. If the trans was rebuilt and the shaft replaced in the incorrect location or with an incorrect shaft, the switch will not function. Relatively easy to check with a continuity meter.

[Rob C.]

Re: 72 LT1 TCS relay

Thank you both for youre help. I did read the service manual and tryed every thing. I will check the transmition switch again. I just thought that there is a way to unplug the relay in the dash and test that.
Thank you,
Rob

[James T.]

Re: 72 LT1 TCS relay

Check that you have voltage to the TC solenoid. If not, cut wires that are taped over does happen. Feel for bulges in the taped harness and look for adhesive wrapping tape, which might indicate someone was inside before you. Good luck. Jim

[Bill C.]

Re: 72 LT1 TCS relay

Just a suggestion ..

I'm pretty sure there is a dedicated fuse labled "TCS" in the fuse block. Take it out and see if it is blown.

You can test the circuit by:
Turn the ignition switch to on/run.
place the car in 4th gear
you should hear a click sound when the CEC seloniod plunger contacts the throttle arm.


Also - have you checked the temp/tcs switch in the passenger head?
it will give full-time vacuum advance when the engin is cold or in a over heat situation. It is integrated into the TCS system.

If all that fails, the there is a TCS delay relay plugged into the harness under the dash. It is usually located very close the tach and the guage cluster.

Just some ideas ---

[Patrick H.]

Re: 72 LT1 TCS relay

You can test the circuit by:
Turn the ignition switch to on/run.
place the car in 4th gear
you should hear a click sound when the CEC seloniod plunger contacts the throttle arm.

Addendum - this usually takes 20-30 seconds to occur due to a programmed-in time delay.

[Jeremy D.]

Re: 72 LT1 TCS relay

The cylinder head thermo switch is usually a nightmare....if you bought a new one from one of the vendors who claim to have reproduced the exact switch for your car, be careful. That little green wire can cause a lot of headaches too. I like Mr. Clupper's idea, too....I can see that happening very easily, and never thought about it. Good Luck!!







An Old beater '71
and a '70 with bald back tires on it...but it's numbers matching!!!

[Rob C.]

Re: 72 LT1 TCS relay

Hi all,
I finly narrowed it down to my TCS relay. Could some one tell me if there is some one thet rebilds them or were I could fine one other than E-Bay.
Thanks,
Rob

[Jeremy D.]

Re: 72 LT1 TCS relay

I know Paragon has them, and they're pretty common swapmeet/Ebay fare...

[Rob C.]

Re: 72 LT1 TCS relay

Thanks.
I will have to coll them on Monday. I cant find it in there book.
Rob

[Jeremy D.]

Now that I opened my mouth...

...heck, I just got their new catalog yesterday....you're right, nada. I even checked Lectric Limited's website...they have the jumper harness, the solenoid, and the switch that's in the cylinder head, but not the relay or the switch in the trans. I KNOW somebody makes the thing, I'd bet if you got the part number & Googled it, you'd find it. Sorry, my bad. And, my parts book is out in the barn, and it's pouring out....