Can someone please tell me what this connector connects to? I have had the 1970 98 for 3 years and just noticed this wire hanging down the firewall. The first pic shows the connector. The second pic shows where it comes from. It is bundled next to the yellow wire and resistor wire that go to the plus side of the coil. Both wires going into the connector are black with green on them, but it looks like the wires were painted green. The car does not have cruise, headlamp delay or Comfortron. Right after I got the car I took out an after-market cruise control system and the wiring strung for a Amm/temp/Oil gauge. It is possible I disconnected the connector at that time and forgot about it in my advanced age. The car runs great BTW

 

ok, I will guess that that is the plug for your AC compressor and should be nearer to the front of the engine?

 

Either AC compressor or the Trans Controlled Spark thermal vacuum switch at the front of the intake.

 

I'd be more inclined to think AC . That style of TCS connector didn't come out till the 71 model year and was only used for 71/72.

 

I'd disagree, I don't know exactly when TCS started for Olds, maybe CA it started earlier. But that resistor I've only seen on TCS type plugs. I know for my 70 GS, the resistors were only used on automatic cars. Manuals had the set-up, but no resistor.

 

You guys are awesome. Thanks for your help. It isn't an A/C wire since it isn't long enough. I went through my manual and read all about the TCS solenoid and thermal switch. The solenoid is no longer there, but the thermal switch is. All three ports are uncapped, so I will check to make sure I'm not losing vacuum from any of the ports. My 1970 manual shows the solenoid and the connector hooking to it. It is possible in 1970 it was there only for California cars. My car was sold in Denver, so it is possible it never had a TCS solenoid. However, the wire and connector I asked about has some bends that appear to have been made permanent over time and if I hold up the wire to where the solenoid should be, the bends fit exactly. Therefore I assume it was there and someone took the solenoid off.


I am assuming not replacing the solenoid, routing the vacuum through the thermal vacuum switch to the solenoid and onto the distributor makes no difference to how the car runs?

 

The TCS isn't going to be critical to your car's operation, in fact a lot of folks bypass that system. I kept mine in simply because I want to keep the engine as stock as possible. I just looked up the TCS for 70 and you're right. My apologies; I was thinking it was a solenoid more like the one in the diagram below. The connector on your wires looks like the ones for the 70 TCS as shown in the 70 CSM.

 

You can't lose any vacuum if the ported switch has no lines going to it. It's purpose was to increase the engine speed by advancing the distributor when the engine reached too hot of a temperature, usually...like in traffic at idle speed with AC on. I've seen those ported switches cut open after use, they get seriously gummed up inside. It's safe to say most original switches do nothing now because of that. Like Allan said, you don't really need either system.

 

Just so we're clear, you don't need the TVS IF you have routed the vacuum advance to straight manifold vacuum. If you are operating the vacuum advance from PORTED vacuum, (ie, no vacuum advance at idle) then you DO want the TVS connected. The whole point of the TVS is to switch from ported to manifold vacuum if the engine overheats. The added advance at idle will help the engine run cooler.

Also, for 1970, the TVS was separate from the TCS solenoid, however the function was the same as for the integrated unit used in 1971-72. As with the combo valve in the disk brakes, the combined valve for TCS used in 71-72 was done simply to reduce parts count and assembly costs.

 

It is on straight manifold vacuum, thanks!