Running an Edelbrock carb and the TCS switch was removed long ago. If I'm getting the factory A\C working again, is it absolutely necessary to run the TCS switch? If so, I'm sure it's tough to get it installed properly on an aftermarket carb. Thanks
The TCS switch? TCS to me is the Transmission Controlled Spark Emissions device on 70 and up 350 and 455 engines. It has nothing to do with the A/C. I eliminate the TCS.
It's whatever switch on the carb that increases RPM when the A/C turns on. I think I saw the TCS switch labeled as doing that.
TCS does not do that. All TCS does is remove vacuum advance until the transmission is in high gear. Zero to do with AC.
You are talking about the idle stop solenoid. Buick used that in 1972 to guard against run on. Due to the leaner carburetor calibrations and higher idle speeds, the engines had a tendency to run on. The solenoid closed the throttle upon shut down. Again, it has nothing to do with the A/C, at least not in 1972. You could wire it into the A/C to make it increase the idle speed when the A/C is on.
Just to explain where I'm coming from as a first-time Skylark owner, I'm totally new to the Buicks. I've been doing a ton of reading and spending what time I can under the hood just to get up to speed. Everything I've owned has been pre-70 Chevys. And none of them came with A\C or A.I.R. stuff. This is a whole other beast. I'm trying to make heads or tails of the HVAC systems so I can maybe get the A\C put back together. Wiring and schematics don't scare me (it's my business) and sorting this car out is a challenge. Especially since the distributor has been swapped to an HEI and the alternator has possibly been upgraded as well. I haven't dug into that yet. I got this TCS thing from the service manual I believe. Maybe because '72 was a weird year with one-off things on it, and the different models (4D, 4L, 4N etc...) were all different as far as systems parts, I might have seen something for a different model. But I definitely saw something on the intake that supposedly kicked up the RPMs when the A\C was used. Maybe that was mis-information or pertained to something other than a 4D Skylark. Either way, mine has neither the QJet, ISS, nor the TCS and I'm not gonna worry about it. Thanks for baring with me. I'm learning!
Page 64-6 of the 1972 Buick Chassis Manual. Again, it has nothing to do with the A/C, but you could use it that way if you wanted.
I use the run on switch to set the carburetor throttle for when the ac is on and when it is off. Works like a charm. I would recommend that you use a relay since the amperage load on that little green wire and reed switch back in the controller in side will have more amps on it. The compressor clutch alone is over 10 amps. The switch and clutch will be wired in series to the normally open side of the relay and the green wire that comes out of the dash to the compressor will wire to the coil of the relay and the to ground
