67 AC blower wiring
Need some advise about my 67 327 with AC , my blower motor only has low and high working with the heater on . And the blower works on low , medium and high with AC on, however medium stays at low speed, I have checked that all connectors are plugged correctly ( I hope ) , have checked the resistor, it appears okay and have checked inside the relay as well, I have put a test light on the Yellow wire at the resistor and it lights up no problem but the LT blue wire only glows half as much , did not get anything on the DK blue' any suggestions ? and yes I gave the relay a good thump.
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Re: 67 AC blower wiring
Terry -- a real head-scratcher
. I'm guessing (and suggesting) that the problem is somewhere in the light blue wiring, or the internal dash switch at the medium blower speed contacts. Sounds like you are not getting 12v on light blue (middle connection) to the resistor. If you have a copy of the C60 wiring diagram from a shop manual or the AIM, you can follow along.
Are you saying that with A/C off, the blower shuts off completely when knob turned to medium setting ? I think the reason your low speed works even at medium setting with the air on is because 12v is always supplied to the yellow wire, even though the 12v supplied by the medium (light blue) connection may be dead.
Thumbnail below is the resistor (off my '65 but should be same for your '67). Left coil and terminal is where yellow 12v supply connects; this is the 'low' speed contact, and voltage is reduced through the left coil (near my thumb) and then proceeds in series through the right coil, for additional voltage reduction, whose terminal (output, dark blue, on the right) feeds final voltage to the relay and on to the blower motor. BTW, other than for high speed, the '662' relay acts only as a 'pass-thu' for the voltage coming off the resistor. On high speed, the resistor is not part of the scenario, which is why high speed always works.
For starters, I would suggest you try jumping 12v from the yellow wire terminal ( or any other 12v source handy) to the middle light blue terminal to see if the blower motor then bumps up to medium speed.
Let us know if that works; if not maybe others can suggest further checks. -
Re: 67 AC blower wiring
Wayne
thanks for the input, I had not realized that when you pull the AC knob that the fan would power up on low without using the fan knob, that through me,I put a test light on the blue wire at the back of the dash switchon medium , It was dead so I am thinking the dash switch has an internal contact issue, what is strange is the yellow at the resistor loses power when switched to medium.
Oh well, found the problem, pulled the wiper switch out ready to pull it apart, pulled the plug of the back of the switch and pushed in back on again,presto , simple poor contact (electric's drive me nuts)Comment
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