I have a 1991 Honda Crx hf. It appears that the radiator fan is always on. It turns on when I turn the key to ACC. But it turns off when I turn the vehicle to off. I tried removing the radiator fan relay but it still turns on with the fan relay disconnected. I have a feeling it's either a bad thermoswitch or bad ground. Any ideas? Thanks!

 

you sure you took the correct relay off and it STILL turned on?



with the relay disconnected, it would need another source for ground for the motor to be powered.

with the relay connected, theres a lot of ways for the relay to be grounded to turn on the fan.

 

I believe both the fan relay and AC relay are connected to one another. And mounted on top of the core radiator support above the passenger side headlights? I also switched the AC relay and cooling fan relay but the radiator fan is always on.

 

Ok, maybe I took the AC relays off instead. I will check again. So you think the relay is bad and not the radiator thermo fan switch behind the block?

 

I don't know what your problem is, and I didn't suggest a problem. I just made two statements.

With the AC relay, there's even more ways for the fan to turn on.

You really need to figure out which wire is grounded. A simple continuity check for each wire to ground is what you need to do.

 

Well, I do not use the AC. Is it possible to just remove the fuse to the AC instead and test it that way? The last owner removed the entire AC unit and cut the wiring to the AC condenser fan. I believe there should be a relay on that wiring as well. I am not completely sure. Does the wiring to the condenser cause any issue if it has been removed? Possibly caused the circuit to not be complete which caused the fan to turn on?

 

Geez man. If the PO ransacked the AC harness, no wonder your fan is shorted.

Just take it all off. I showed you both circuit diagrams.

 

Sorry for my ignorance. Take what off? Also, it was working fine until couple of days ago. I purchased the vehicle 4 months ago. The cooling fan would turn on and off by itself.

 

A quick way to rule out the coolant temperature switch is to just unplug it. If the fans stay running while it's unplugged, it's not the switch.

 

Remove all the cut ac wiring. Check for shorts to ground at least.

 

I just unplugged the fan relay and it turned off. So it's not the relay. I will check the fan switch tomorrow. Where is the diode?

 

Thank you guys for the help

 

Diodes are embedded in the A/C harness.

 

Ya, the diodes are on the ac loom INSIDE the car near the blower. Just remove the loom if it's messed up and you are not going to use the ac system. It unplugs. No need to cut stuff.

 

If you're not going to ever use the stuff again it's better to just eliminate it in my opinion. Gets it out of the way, simplifies maintenance and WOW(!) weight reduction of a few ounces :D

 

Didn't get a Chance to remove the AC wirings yet. But do I have to remove the entire dash to get to the AC wirings within the cabin? I suspect it may be the radiator switch behind the block. Again, I didn't get a chance to remove it yet. But the AC wiring loom is also housing the headlight wirings.

 

The coolant temp switch on the back of the block is extremely simple to diagnose. Just check for continuity across the two terminals.