Hi all, I have a 99 escort zx2 that I would like to wire in an external set of relays to engage the a/c compressor and turn the cooling fan on high. Here's what I want to do, but I have a couple of questions. But first things first... I found a bad WAC relay for the a/c compressor clutch in the CCRM, and tried (with little finesse) to replace the relay... Oops, I made the circuit board junk for soldering in a new WAC relay by losing patients and yanking the old relay out (it came out all righty :devil
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I want to hook up a toggle switch to a relay that will close a switch to ground pin 17 (Which should close the switch for the cooling fan on high speed). Also, my toggle switch will close another relay that will switch hot to pin 23, which should engage the a/c clutch. But instead of just switching the a/c clutch on, I want to send the circuit through the low and high pressure switches in the a/c system.
Question #1. If I ground pin 17 (Which is what the PCM does to turn the cooling fan on high), is it going to screw up the PCM? If so, should I install a diode so it doesn't ground where ever pin 17 goes to in the PCM?
Question #2. Does the high pressure switch actually operate as a switch? I recall reading somewhere that the high pressure 'switch' is actually a rheostat that signals the PCM to tell it how high the pressure actually is (instead of just opening a switch when the pressure gets too high on the high pressure side). It seems like both low and high pressure switches have more than 2 wires, so....
Quesiton #3. Which wires should I use on the low and high pressure switches to wire the hot wire to my compressor clutch?
That way I get the a/c to turn on, along with the cooling fan on high when I flip the switch that I will install. But, if the pressure gets too low, or too high in the a/c system, the appropriate switches built in to the a/c system will disengage the a/c compressor.
I'm not concerned with the WOT relay. I don't drive it like a race car, and I don't ever think I floor the accelerator anyway.
Thank you so much for any help you can offer.
Jason
I want to hook up a toggle switch to a relay that will close a switch to ground pin 17 (Which should close the switch for the cooling fan on high speed). Also, my toggle switch will close another relay that will switch hot to pin 23, which should engage the a/c clutch. But instead of just switching the a/c clutch on, I want to send the circuit through the low and high pressure switches in the a/c system.
Question #1. If I ground pin 17 (Which is what the PCM does to turn the cooling fan on high), is it going to screw up the PCM? If so, should I install a diode so it doesn't ground where ever pin 17 goes to in the PCM?
Question #2. Does the high pressure switch actually operate as a switch? I recall reading somewhere that the high pressure 'switch' is actually a rheostat that signals the PCM to tell it how high the pressure actually is (instead of just opening a switch when the pressure gets too high on the high pressure side). It seems like both low and high pressure switches have more than 2 wires, so....
Quesiton #3. Which wires should I use on the low and high pressure switches to wire the hot wire to my compressor clutch?
That way I get the a/c to turn on, along with the cooling fan on high when I flip the switch that I will install. But, if the pressure gets too low, or too high in the a/c system, the appropriate switches built in to the a/c system will disengage the a/c compressor.
I'm not concerned with the WOT relay. I don't drive it like a race car, and I don't ever think I floor the accelerator anyway.
Thank you so much for any help you can offer.
Jason
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