2012 ford transit no cooling fan speeds (underhood)

2.0 overheating found the fans were not coming on. checked relays not getting ground from pcm. used autel and turn the fans on still not coming on. checked at pcm to eliminate a broken wire im getting 12 volts at pin 18 and 34 but the pcm isnt pulling it to ground. backprobe those pins use test light to pull down to ground fans work! does this sound like the pcm is the issue here. Going to check powers/grounds tomorrow. and going to check amperage draw on the speeds. Does anyone know an amperage on these fan motors??

Went digging for a diagram, could only find a 2011. It sounds correct based on the PCM pin numbers?



Dunno about the cooling fan current draw... 30-ish amps at high speed would be my guess. But still, since the PCM controls the relays, I'm not sure that a fan draw problem would cause this. :huh: I don't suppose the fans come on with the A/C?

Not sure what the temperature the PCM has to see for the fans, but you've likely looked at that already. A pin tension issue on both pins is unlikely, as would both clamping resistors in the relays failing.

Please tell me this isn't the same Transit that you already replaced the computer for a downstream O2 issue! :lol:

no fans dont come on with the ac. the complaint from the customer is runs rough, and over heats. found it had a bad intake gasket. and to answer your question it is the same one!

also forgot to mention fuse 16 and 17 were both blown.... so im going to do an amp clamp on it tomorrow while grounding the high speed fan pin at the pcm with a test light. the blades didnt feel tight or anything they spin with no resistance..

cheryl hartkorn wrote: and to answer your question it is the same one!

:lol: This Transit has led a rough life! Or these newer Ford PCM's are just made of glass. :silly:

also forgot to mention fuse 16 and 17 were both blown.... so im going to do an amp clamp on it tomorrow while grounding the high speed fan pin at the pcm with a test light. the blades didnt feel tight or anything they spin with no resistance..

Ahhhhh now I understand why you wanted to measure the fans. I don't suppose there's any codes stored that might prevent fan operation?

none. no codes.

Any luck with measuring the fan current draw? Still can't put together why the fuses popped...

found a bulletin aout on it. saying reflash the pcm etc. should be on bbb industries.com

Interesting... The TSB indicates that the resistor can cause the high speed fuse to pop, but I dunno that I agree. :lol: Anyway, your resistor isn't open, so I guess it's just down to reprogramming?

I have a love/hate relationship with TSB's - Good at explaining how to fix stuff, but never explains the WHY.

well i think we can call this one fixed. i was using the autel ds708 went into there functional tests in ford tried to turn on both fan speeds nothing. replaced the resistor. did the test they have you do in the bulletin. reflashed the pcm to the latest calibration. everything started working right. hooked autel back up tried functional test again still nothing. must be an issue with the reverse engineered software. hooked up old school verus (dont use it much its just to slow) ran the key on engine off test fans cycled

Never helps when the tooling throws a wrench into the mix.

Any more, I'm convinced that you Need two brands of scanners if you're using aftermarket equipment. No one brand 'does it all'. Just this week, I was working on a New Beetle with a lean code. I KNOW that VW uses idle and part load fuel trim values, but the Snappy wouldn't show them. Switch to the Autel, and bam, I'm in business.