Thermal Vacuum Switch

[Jeff Carollo]

On my 79 L-48 I have 3 TV switches. I was able to locate replacements for the EGR and EFE, but cannot find a source for the Spark TVS that goes to the distributor...anyone know where i can get one ?

[Joe L.]

Re: Thermal Vacuum Switch

Jeff-----

The switches that you currently have should be GM #373510 (aka Delco #212-352) and GM #14009008 (aka Delco #212-61). The one that you need is GM #355961 (aka Delco #212-12). This is a replacement for the original switch which was GM #3031549. Consequently, it likely will not be confiugured just like the original, but it should be 100% functional. The GM #355961 is still available from GM for a GM list of about 17 bucks.

I'm not surprised that you're having trouble locating it. I'll bet that there isn't a GM dealer in the country that could come up with this part number on the basis of the information that is available to them.

[Jeff Carollo]

Re: Thermal Vacuum Switch

So, these switches are rated at different temperatures, but they may look the same ? I think I can match by color, right ? The purple switch controls the EGR and is mounted on the intake manifold...and the Spark switch should be blue and mounted in the thermostat housing ? or is it EGR Blue, and Spark purple ?I'm totally confused.

[Paul L.]

Re: Thermal Vacuum Switch

My former 1979 L-82 did not have the third switch (see pic). But it had yellow as EFE and purple as EGR. So by process of elimination I am going to guess blue. BTW they are configured differently in a physical sense. The vacuum hose sockets tell that story: yellow and purple mating is different.

[Joe L.]

Re: Thermal Vacuum Switch

Paul and Jeff-----

The 79 L-82 did not use the third thermal switch. For L-48 applications I believe that it was installed in the second fitting in the thermostat housing. I thought that L-82s used a thermostat housing with a plug in the second fitting. However, from the picture I note that yours has one with an unmachined fitting boss. What is the embossed part number on this housing?