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Discussion Starter · #1 ·
Trying my luck here, cause im at a dead end.
1991 crx si
Ive done the climate control control swap to the Accord unit. Everything is wired correctly, and all functions work.
However:
The ground wire coming out of fan speed selector switch heats up too hot to hold with fingers. I have not soldered the connection yet due to this problem.

All grounds are testing good, have either been cleaned, replaced, and or upgraded.
I have 2 accord units, both do the same
New: fan speed selector switch, blower resistor.
I bypassed wiring harness by taking the ground straight to negative on battery, no change, still gets too hot.
Could there be too much voltage coming in to the unit?
 

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voltage is gonna be a constant car 12 volts, its too much current that causes a wire to get hot. negative IS ground just to clarify. im not as familar with the accord unit swap, is this a power wire thats suppose to go through the blower motor resistor or something? is this cirtuit fused? a hhot wire means too little resistance, something is either shorting and doest have a fuse, or the resistance is very very low. remember I=V/R thats voltage divided by resistance equals current (which is your heat problem).
 

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Not to be an a$%$# but just to clarify some information.
This is one of the problems
I bypassed wiring harness by taking the ground straight to negative on battery, no change, still gets too hot.
Ground is better short AND using the correct gauge of wire. If you are wiring a ground to a further location you need to increase its thickness to decrease resistance. It all depends of how long away. Audio guys knows this perfectly.

a hhot wire means too little resistance, something is either shorting
This is the other way around. Thin wires Increase Resistance, thick wire decrease it.

Test for a possible short circuit.
you need a multimeter to test wires for continuity. Positive to Ground should be zero. And zero voltage between chassis Ground and the Ground cable terminal from the wiring plug.

Unplug Neg battery cable only and set multimeter to DC voltage now probe the Ground terminal at the plug with the Red probe and the Black probe cable to chassis( still battery Neg disconnected) it should be zero volts.

Current flows from Negative to Positive.

You need to find the resistance values for your blower motor and its Resistor Box.
Then compare those values with the Accord values.
 

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Discussion Starter · #4 ·
Yeah to clarify, I bypassed the ground with larger gauge and similar gauge wire straight to neg post for testing only. The results were the same (no change). But what the results told me was there is not a problem with something shorting to the ground wire because with a completely new and bypassed wire, the results were the absolute same. I shortened the ground to a known and tested good ground behind the radio structure, also no change. Volts are zero with battery neg off and battery voltage present with neg cable connected as it should be. Ground tests less than 0.05v with car and climate control running (acceptable range).
I would like to compare resistance values of my blower motor, and resistor. to the accord values, but the accord values have proven difficult to find if I don't have an actual working honda accord to test myself. I was unable to find values for the crx or accord online, I have the crx because I did the test. Unfortunately not even the hanes manual with wiring diagrams gives resistance values.
Theres a few other issues with the car im dealing with little by little.
 

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I was unable to find values for the crx or accord
A visit to a local junk yard may give that information.
Btw
Does it overheats on all fan speed positions or just 1?

Which one(s).
Speed 1 has the highest resistance to slow down the B motor the most.
Highest speed has basically no resistance. If the fastest speed is overheating, there has to be something wrong with the wiring or the climate control unit itself.
Try measuring resistance on the speed control switch unit itself.

Is the blower motor new?
An old worned out blower motor could be on its last leg and increasing resistance to the R.Box.

Or clean? If the hamster wheel blades are dirty , it wont flow the correct cfms. This one is very common on residential ac units( I always keep an eye on ours).

The resistor box gets cooled down by the air blowing through; may be the resistor box is not sitting deep enough to get cooled down.
 
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