Electrical Fan Spins Intermittently

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I ended up not being able to test tonight because I couldn't find my other test leads. I needed the first set for it's probes at the end that I used for apply ground and voltage, and the other leads to use with the multimeter to test voltage at the fan connector.
Though, I thought we confirmed that there were volts at the High speed fan output (fan connector) when we tested it and found voltage that matched the output pins. But I don't mind testing the relay in specific.
 
I ended up not being able to test tonight because I couldn't find my other test leads. I needed the first set for it's probes at the end that I used for apply ground and voltage, and the other leads to use with the multimeter to test voltage at the fan connector.
Though, I thought we confirmed that there were volts at the High speed fan output (fan connector) when we tested it and found voltage that matched the output pins. But I don't mind testing the relay in specific.
I think you did, but once parts are swapped out (like the CCRM), things can change.

With your old CCRM, since you said you had voltage at the high speed fan connector with pin 17 grounded, one could have only bench tested the other fan (not touching the CCRM). One could have just set the Taurus fan near the front of the car and used jumpers to connect it to the outside terminals of the fan connector.
 
If everything is working up to and going out of the CCRM then you have a wiring issue plain and simple. So you need to either change the wiring from the CCRM to the fan or inspect it closely and find the problem with it and repair it.
 
I think you did, but once parts are swapped out (like the CCRM), things can change.

With your old CCRM, since you said you had voltage at the high speed fan connector with pin 17 grounded, one could have only bench tested the other fan (not touching the CCRM). One could have just set the Taurus fan near the front of the car and used jumpers to connect it to the outside terminals of the fan connector.
The Tarus fan plugged right into the connector so I did just that with the original CCRM without touching it and it did nothing, then I tested the fan and it spun with direct ground and voltage from the battery.

If everything is working up to and going out of the CCRM then you have a wiring issue plain and simple. So you need to either change the wiring from the CCRM to the fan or inspect it closely and find the problem with it and repair it.
If I find the time tomorrow I'm going to look it over inbetween the output to the fan then.


Along with testing the relay in specific first, that way I can absolutely rule out the CCRM, as many times as we have.

If I can't find it, I'm left with two options, number one buy and splice in that segment of the harness, then correct CCRM until it spins. Or two go with an aftermarket controller, I believe this is the controller I'd go with (cheap, simple) http://www.summitracing.com/parts/sum-890016
 
You'll need at least a 40 amp relay to operate the stock fan. That 30 amp setup in your link will eventually melt down. The 40 amp relay that we already have is really too small for this application, but it does last 15 years on average so I'd say it's ok.
 
Unless you use a balanced 160* t-stat, once up to temp, your fan will probably never shut off (the mechanical t-stat will close before you reach the fan-off-temp of 170*).

You want to have the fan-off temp be 5-10*F higher than the temp that the mechanical t-stat actually opens fully. If your 180* parts store t-stat opens fully at ~ 192*F, you'd want the fan to come on at about 210* and turn off at about 200*.
 
You'll need at least a 40 amp relay to operate the stock fan. That 30 amp setup in your link will eventually melt down. The 40 amp relay that we already have is really too small for this application, but it does last 15 years on average so I'd say it's ok.
Unless you use a balanced 160* t-stat, once up to temp, your fan will probably never shut off (the mechanical t-stat will close before you reach the fan-off-temp of 170*).

You want to have the fan-off temp be 5-10*F higher than the temp that the mechanical t-stat actually opens fully. If your 180* parts store t-stat opens fully at ~ 192*F, you'd want the fan to come on at about 210* and turn off at about 200*.
Gotcha both, 40 amp and more reasonable temperatures for it to start spinning and end spinning, I though the 170 was a little unreasonable.
 
Just a note, my mom was tired of me driving her mazda 6 (as am I, since the fuel economy is about the same as the rustang) so she told me to order a 'new' ccrm(yah know those ads that salavage yards post). Did, and didn't solve the problem so probably the wiring.
 
I'm now heartbroken and split between what to do. Do I cut it all up and cut in another factory harness, or do I tuck it all and get the aftermarket controller? It's a sad sad day ;(
Given how the diagnostics have proceeded so far, it's probably a safer bet to go aftermarket because it will be a stand-alone system and not reliant on any possibly bad OEM wiring.

Be sure to research what method of control you want to use, what components will be used, what the installation will entail exactly, and what the cost will be [in totality] before making your decision
 
Since there are only a few engine bay harnesses and they are all modular in design, I'd just swap in a different harness. I believe the CCRM and fan circuits are part of the computer harness that runs into the firewall to the computer. It's not all that bad to change that harness. The issue will be finding one!
 
Given how the diagnostics have proceeded so far, it's probably a safer bet to go aftermarket because it will be a stand-alone system and not reliant on any possibly bad OEM wiring.

Be sure to research what method of control you want to use, what components will be used, what the installation will entail exactly, and what the cost will be [in totality] before making your decision


Since there are only a few engine bay harnesses and they are all modular in design, I'd just swap in a different harness. I believe the CCRM and fan circuits are part of the computer harness that runs into the firewall to the computer. It's not all that bad to change that harness. The issue will be finding one!

And now I'm stuck again on what to do, again my very partial to the whole stock thing, even if it's pretty prone to failure and badly designed.

It'd cost the same either way I figure. The hardest part would be swapping the pins on the back of the EEC, but in the grand scheme it isn't that much work and keeps the stock-ness, for now.

If I find one easy enough or pull one from a car here soon then that'll be it. If not, i'll be forced to buy an aftermarket one.
Nothing wrong with the aftermarket controller, it'd be great for a a9l computer swap in the future but no money to really do the mods any time in the near future.