C-2 high blower speed

[Dale S.]

My 67 SB 4 sp with A/C has no high blower. The compressor runs and I have low and medium blower. The ground is good, I tried another relay ( blower) and the resistors are good. The only thing I have not checked is the blower switch in the dash. Is there something I should check before I go there? I checked the Archives and saw to check the ground to the starter, resistor and relay. Any help would be appricated. Thank you Dale

[Jack H.]

Re: C-2 high blower speed

Check out your copy of the AIM book, option section, C60 air conditioning and you'll find a separate wiring diagram dedicated to A/C. You'll note the presense of a discrete, in-line fuse on the wiring path that supplies power to the blower fan for hi/max speed operation and that line connects to the engine compartment B+ buss bar (side of horn relay) and runs to the blower motor relay mounted on the Harrison air box duct.

The symptoms you describe (fan works on low speeds but NOT on hi/max setting) are typically the result of two things:

(1) The in-line power fuse is blown or, more commonly

(2) The blower fan relay has a burned contact in its hi speed stage

[Dale S.]

Re: C-2 high blower speed

I found the problem, the red wire that runs from the horn relay to the blower relay on a 67 with A/C had been spliced behind the distribitor with a squeeze type connector and covered with the a piece of old cloth masking tape. Must have been done for some reason before I got the car in the early 70's. The blower hi speed is now fine. Thanks to the reponder. Dale