hey jamiegmr- that switch from madvet.com works great i have been running it on my car for a year now. and i love it comes on at 200* and off and at 185 on the dot. now i also had jet switch is should come on at 195 and off at 175 but for some reason wouldnt come on till 220 and would go off at 185 i dont know why? and other thing i put a stock one in just to see and sometimes it got to 225 sometimes higher but i would shut it off if it got that high i dont let my car get past 230. im telling you go buy the one from madvet.com the switch it self is like $16.99 and with shipping like 24 bucks of you can also get the wiring harness which is just the connector for like 25 bucks but it has to be a dual fan set up. good luck. Later Daniel

 

Field report: I Installed the P/N 35930 temp switch from Advance auto, looking for a lower "ON" temp. I am glad it was only $7, because it does not turn fan #2 on until over 240 F. It actually turns on at a slightly higher temp than the old stock switch did. I either was given one with inproper calibration, or we should look elsewhere for a switch with a lower closing temp.

 

The product description for P/N 35930 says "radiator fan switch", nothing else. Didn't find any temperature specs.
It might be just a direct replacement for the stock switch which does exactly what you described: it turns on the fan at around 240F.

Lou

 

Yes, it looks like it is just a stock switch. Post #50 in this thread said that part number was for a Buick GN, and it is known that the correct GN switch is a lower temp switch than a 3rd gen. Rather than research it farther, I spent the big $7 and 30 minutes time and took a chance. After doing a little searching, it turns out the Advance auto p/n 35930 is listed for numerous GM applications, not just a Turbo Regal. There are several switches that can be used, with no info on open/close temps. Sometimes I long for old days with a parts store with paper catalogs.

 

According to Rockauto.com the correct part number is 35946, but they want $18.59 for it.

 

Discussed the "white crap" (teflon pipe tape) with a mechanic and he said it will cause problems because the switch works by providing the ground to the block when it activates. If you use teflon tape, it insulates the connection and may not properly activate the fan relay. That's not to say that it can't work, but since they are already brass pipe fittings, you *should not* use it.

 

For those of you that are thinking about adding a second fan you can't just connect it to the stock wiring that controls the stock fan. You install a totally separate circuit from the stock one. The adjustable fan switch 3647 that willie suggested comes complete and has the relay already installed so you don't have to mess with it. Its very easy to wire in and then you will have a fan you adjust to whatever temp you want it to kick on at. This way the new fan can be the primary and the stock fan will still be there as back up if you need it.
Most of that also goes to the guys wanting a single fan to be adjustable. You just bypass the in head switch and install this one. Real easy.