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Discussion Starter #1
New to the forum and my first post. Here's the short version of my first question:

Does anyone know where the circuit breaker for the AC/Heater blower motor is for a 68 Galaxie with a 302?

Here's the long question:

Blower motor will run fine on low but if you switch it to medium or high it will run for about 30 seconds then stop. It will come back on in a minute or so but then will run again for about 30 seconds (on medium or high) and stop again. But it runs constantly on low.

Originally thought it was a bad blower motor (worn brushes or something) so replaced it, twice (once with a used part, once with a new part), and the same problem occurs.

Next tried to check for bad ground. Jumped the ground directly to the frame and would run for bout 30 seconds then stop. When I initially made the jumper ground connection I'd get a spark and the blower would run. After about 30 seconds blower would stop. I'd try to reestablish a ground connection but I would get no spark. After about a minute or so I'd get a spark again and the blower motor would run again for about 30 seconds then stop. The issue of no spark now makes me think I've got something going on on the positive side of the circuit.

I began working backwards from the blower motor through the positive side of the circuit to isolate the problem by running the blower off a jump pack:

1. Blower to resistor connection--good
2. Resistor--good
3. Resistor connector to 3-prong connector from the switch--good
4. Switch 5-prong connector at the back of the switch to the blower (through all three poles of the resistor)--good

At this point I realize I have a connection issue either from the fuse box to the switch or from the ignition switch to the fuse box. I got power to the other accessories that feed of the ACC side of the ignition switch (only tried wipers since the radio doesn't work) and I get power to the wipers so I figured that the problem had to be the connection between the fuse box and the blower switch.

I took out the fuse box and discovered that there is NO connection from the "heater" fuse back to the blower motor. Couldn't figure that out. I thought some previous owner must have jacked around with the electrical system so I took out ALL the fuses to see which circuit had the blower motor running on it. NONE of them did--the blower would run in the ACC and RUN positions with no fuses in the box.

So there has to be a circuit breaker somewhere.

I've looked at the wiring diagrams for the 67 and 68 (my 68 was manufactured in March of 67 and has some of the AC components that were used on the 67) but both of the diagrams I had access to did not show AC--the blower switch on these diagrams shows 4 wire connector (Black, Orange, Red, Blue), I've got 5 (Green for AC, Yellow for power, and Orange, Blue, & Red for High, Medium, Low). I can trace the yellow wire back only so far behind the dash and loose it somewhere behind the bottom left passenger AC vent. To trace it from there I'm going to have to take out the entire dash and I'd rather not do that if it can be avoided.

I know there has to be a circuit breaker somewhere and that it is switched through the ignition but can't find it. Anyone know where this might be or have access to a wiring diagram that shows a 68 with factory AC?

Thanks for any help!
 

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My wiring book (1965) shows on the "economy" A/C there is a 15 amp in-line fuse between the switch and the ignition. On the Selectare there is a circuit breaker that sits on stud atop the back end of the ignition switch connected to a yellow wire that runs to the 5-prong switch (pic).
For the heater, the fuse is in the fuse panel.
 

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Discussion Starter #3
Thanks for the response. I'll have to check at the ignition switch and see. I thought the design of the ignition switch changed for the 68 model year. I had to replace it a couple of years ago and don't recall any additional electrical element attached to it but my memory could be wrong. This is at least a start in tracking this down! Apparently from what I'm seeing if the vehicle has AC the heater fuse is not used. Since your diagram shows power coming directly from the ignition this would make sense.
 

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Discussion Starter #4
I finally found the location of the AC/Heater blower circuit breaker in my 68 Galaxie. The shop manual shows the location of a circuit breaker but the part number corresponds for the windshield wipers. I found the AC breaker connected to and behind the windshield wiper breaker. This is all located between the cigarette lighter and the left passenger AC vent behind the trim piece. Fortunately I didn't have to rip out the entire dash to get it out. Old breaker had a bad terminal. New breaker is in and blower runs great.
 

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Congratulations and thanks for posting the follow up.
 
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