I need an electrical guru here.
I am totally lost, and while I have a understanding of the electrical system, it is NOT my best area of knowledge once you get into a serious gremlin. I am handy with a test light, but that's about it.
I have gone through all the basics, like replace this, test that, and check wire connections. I have also tried 4 CCRMs total in the last 24 hours.... The stock one, a used crusty stock one from the u-pull, a used (but new looking) Ford parts counter replacement CCRM from the u-pull, and a brand new CCRM last night when we got desperate. They all acted totally the same. They ran every function that they were supposed to run, except the fan, on either speed, for any reason.
So, right now this is where we stand:
*1994 GT
*The circuits involved all remain stock.
*Wires visible all appear undamaged, connections tight.
*New CCRM is currently installed. We still have the original and the Ford brand replacement as well. The crusty 94 OEM box was used for the core charge and is no longer in our hands.
*The fan works fine when jumped straight to a 12v power source, ruling out failure of the fan unit itself.
*New ECT installed. Still have the old one, kept it just incase.
Some testing and observations:
Fan works with direct 12v applied.
60a Fan maxi-fuse has power on both sides.
Used a test light on the fan when it was supposed to be running, in order to rule out bad connection at plug, and no power to the plug.
CCRM replaced as noted.
Turning on the a/c will NOT run the fan.
Chip is tuned to turn the fan on at 180*, but we ran it with and without the tuning just to make sure it wasn't a chip problem.
There is a 10a regular fuse in the power distribution box under the hood that it's name sounds like it might be connected to the fan operation. It does not have power to either side of the fuse, or either connection when the fuse is removed from the block. I am not sure that it even should, or ever has had power to it. (Key on, key off, or running, it's the same result.) Fuse is good. Just for giggles, since that 10a fuse had no power to it, I put 12v to the feed side of the fuse... Nothing happened except my son said the CEL flashed when I applied the juice. I know this was not a sound test procedure, but I figured if it's a fuse in the power distribution box, it can handle 12v and it's not like it's one of the circuits with 5v going to the PCM or any sort of 'fragile' circuit. Doesn't matter nothing happened, no sparks, and checking the circuit for a short with a test light came up negative. The CEL may have been coincidental.
I have access to a code reader, but not until later this morning.
If that shows anything, I'll post it. The last time I used my son's code reader on the 94, it tested the fan by running it, and it checked out, but that was a month or two ago, before the fan symptoms came about.
Now that you are thoroughly confused like me, I'll throw in one other strange observation:
The fan began running in low speed all the time, like the relay was stuck in the on position about 2 weeks ago. It ran all the time like this for a week, and now it hasn't run at all in about it week.
I just assumed this assured it was the CCRM... I figured the relay was stuck on, and then when it finally shut off, it has been stuck off. Problem solved, replace CCRM. Didn't work.
Any help that doesn't involve looking at schematics? I looked at those for the fan/CCRM, and got completely befuddled, just like any time I try to understand a wiring diagram.
I am totally lost, and while I have a understanding of the electrical system, it is NOT my best area of knowledge once you get into a serious gremlin. I am handy with a test light, but that's about it.
I have gone through all the basics, like replace this, test that, and check wire connections. I have also tried 4 CCRMs total in the last 24 hours.... The stock one, a used crusty stock one from the u-pull, a used (but new looking) Ford parts counter replacement CCRM from the u-pull, and a brand new CCRM last night when we got desperate. They all acted totally the same. They ran every function that they were supposed to run, except the fan, on either speed, for any reason.
So, right now this is where we stand:
*1994 GT
*The circuits involved all remain stock.
*Wires visible all appear undamaged, connections tight.
*New CCRM is currently installed. We still have the original and the Ford brand replacement as well. The crusty 94 OEM box was used for the core charge and is no longer in our hands.
*The fan works fine when jumped straight to a 12v power source, ruling out failure of the fan unit itself.
*New ECT installed. Still have the old one, kept it just incase.
Some testing and observations:
Fan works with direct 12v applied.
60a Fan maxi-fuse has power on both sides.
Used a test light on the fan when it was supposed to be running, in order to rule out bad connection at plug, and no power to the plug.
CCRM replaced as noted.
Turning on the a/c will NOT run the fan.
Chip is tuned to turn the fan on at 180*, but we ran it with and without the tuning just to make sure it wasn't a chip problem.
There is a 10a regular fuse in the power distribution box under the hood that it's name sounds like it might be connected to the fan operation. It does not have power to either side of the fuse, or either connection when the fuse is removed from the block. I am not sure that it even should, or ever has had power to it. (Key on, key off, or running, it's the same result.) Fuse is good. Just for giggles, since that 10a fuse had no power to it, I put 12v to the feed side of the fuse... Nothing happened except my son said the CEL flashed when I applied the juice. I know this was not a sound test procedure, but I figured if it's a fuse in the power distribution box, it can handle 12v and it's not like it's one of the circuits with 5v going to the PCM or any sort of 'fragile' circuit. Doesn't matter nothing happened, no sparks, and checking the circuit for a short with a test light came up negative. The CEL may have been coincidental.
I have access to a code reader, but not until later this morning.
If that shows anything, I'll post it. The last time I used my son's code reader on the 94, it tested the fan by running it, and it checked out, but that was a month or two ago, before the fan symptoms came about.
Now that you are thoroughly confused like me, I'll throw in one other strange observation:
The fan began running in low speed all the time, like the relay was stuck in the on position about 2 weeks ago. It ran all the time like this for a week, and now it hasn't run at all in about it week.
I just assumed this assured it was the CCRM... I figured the relay was stuck on, and then when it finally shut off, it has been stuck off. Problem solved, replace CCRM. Didn't work.
Any help that doesn't involve looking at schematics? I looked at those for the fan/CCRM, and got completely befuddled, just like any time I try to understand a wiring diagram.