C3 - 1970 Heater fan blower switch

[Jim K.]

Finally getting around to reassembly of the dash and console on the 70. After rebuilding the heater control wheels and such I noticed that the electrical spades on the back of the fan blower switch were very loose, so I took it apart and peened them tighter. No problem. When reinstalling the slide, I realized that I didn't keep track of the slide position and it looks like it can go in one of two ways. Before I bend the tabs back over to seal it up, can someone help me understand what the wires do in terms of switch position and hi, med, low and off. I have included a sketch (I hope) of what I think is the off position. If someone knows that in a certain position there should be closed or open circuit between certain spade connections, I can tesdt it at home... I suppose I could just plug it in and try it that way, but I don't like electrical fires
Thanks!!!
Jim
OK, that didn't work, I was trying to post a PDF that I drew showing the switch and spades, but it didn't work... so close your eyes and imagine 3 spade connections side by side numbered 1, 4 & 2 with a 4th spade labeled 3 offset from the row but between #'s 1 & 4. Sure, simple... Thanks!!!

[Jim T.]

Re: C3 - 1970 Heater fan blower switch

I have replaced a bad switch in my 70, wish I knew where I put the bad one. However the thought I have is the switch when put on high does not pass the the electical power actually through this switch, the electrical power comes from the increased wiring size that has the inline fuse in the vicinity of the master cylinder. Don't know if this helps or not Jim. Is there any helpful information in the service manual?

[Joe L.]

Re: C3 - 1970 Heater fan blower switch

Jim-----

If you have any concern about the safety or functionality of the switch, you can still get a new one from GM under the original part number. It's GM #3909028 and it GM lists for $21.27. I believe this switch is identical to the original.

[Jim K.]

Re: C3 - 1970 Heater fan blower switch

Thanks Jim and Joe:
I did a continuity test with an ohm meter and it checked out o.k., then a quick check in the harness and I got it right! HMMmmm, I won the Derby pool Saturday and got this right on the first try, I'm going out and getting a Powerball ticket!!!
Thanks!!!
Jim