There should be a relay that controls the fan high. Not the resistor. It should be mounted just beside and above the resistor.
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Cool Breeze Thread...Need an '88 Wiring Diagram!
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The fan high speed bypasses the resistor, gets a fat 12 volts from the relay. Dad works at a Dealer? You don't need us!
I would check the red wire from the relay it will tie into the alt and distributor +. make sure it wasn't disconnected during an engine swap.
Sure I do, while I appreciate his help, I like to get a general idea of what's going on before I ask for his help. 😉
There is a relay that operates only the high setting on the blower fan. The hi setting on the blower gets full 12v power from a relay mounted on the AC box. That same wire is in the same circuit as the red wire on the ALT and the red wire to the distributor. The relay should have a red wire, orange wire, blue wire, purple wire and black wire going to it. The blue wire comes from the resistor. The orange wire comes from the blower switch. black goes to the blower motor and ground. the purple goes to the blower motor. So what I suggest to find the problem is to make sure the red wire is still connected in the ignition circuit. You can also look at the other wires to make sure they're all still connected but they most likely are. If all of that checks out then it will be a bad relay. Which it probably is anyway, but I have seen the red wire get eliminated in engine swaps.
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Here is the harness I have. The relay was mounted on top of the heater box. I believe the two prong connector plugs into the A/C compressor. As for the rest im not sure. Aside from the relay being mounted none of the wires were plugged into any connectors or anything
Ignore the ancient Ford Tech patches lol. Also this plug is the one where the red wire is cut.
Not sure what this one is at all, looks like a weather pack connector, maybe for the carb on the 307?
Ignore the ancient Ford Tech patches lol. Also this plug is the one where the red wire is cut.
Not sure what this one is at all, looks like a weather pack connector, maybe for the carb on the 307?
Also are we talking about the same relay? I just ordered this one. It's on top of the heater box. I think it has all the color wires you mentioned. The high setting has worked in the past, and it just stopped one day. So I'm assuming it's not from a cut wire
Also sorry, I keep forgetting to quote posts to reply to them, I hope it doesn't make things too confusing.
For the AC harness you should only have a light green wire and a dark green wire. Light green comes from the AC control head in the dash and goes to the pressure cycling switch, then it and a dark green wire come out. The dark green goes to the compressor clutch, there should be a black ground in the plug for the compressor as well that goes to the compressor frame. The light green goes to the idle solenoid, it grounds itself.
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