How do I check the high speed fan circuit?

[Zero Signal]

I know my low speed works since it will come on with the A/C. But it will only stay on long enough to bring the temp down, at which point it will stay cool untill the temp rises high enough to switch it over to high speed. But instead of going to high speed, it shuts off.

So this leads me to think the high speed circuit is toast and it doesn't seem too improbable with all the fan issues we have. SO then, how would I test the circuit? I'd like to fix it without routing a switch and I can't see any burned wiring. Would a typical digital code reader tell me?

If this is the source of my overheating problem, I'll be ecstatic

 

[GTPhreak]

I thought the high speed ran with the a/c? dunno how to test it, but if you ground pin 17 at the ccrm it should kick on the high speed fan

 

[Zero Signal]

Is that the high speed? Hmm. . .I'll have to get my hands on a code reader I think. For some reason, in the back of my head, I sorta thought that the A/C kicked on the high speed, but wasn't sure. I wonder if the ECT is being wierd (it's a brand new one) or if the CCRM has issues?

 

[94GTLaserRC]

The low fan comes on with the A/C if the car is not at the computer temp yet. The high will come on at a lousy stock setting of 220+*

If you get the $25 code reader from Walmart (which you should have anyway). The first test it does it the low and high fan check. You will know right away.!
RC

 

[GTPhreak]

If you get the $25 code reader from Walmart (which you should have anyway).

Or a .02 cent paper clip which will do the same thing for a fraction of the cost

 

[94GTLaserRC]

Or, you can use a butter knife instead of buying a screwdriver!

Common dude, anyone serious enough to be on this board asking questions on HOW TO... should own a code reader!!!
RC

 

[stangboy]

My high speed fan doesn't come either. It hasn't in a long time, which is the reason I always have a cooling problem during the warm part of the year. I was thinking about getting an additional fan to be a pusher instead of a puller like the stock one. So, when mt tem starts to get higher than I'm comfortable with I'll just turn the pusher fan on.

 

[GTPhreak]

anyone serious enough to ask how to should know that a code reader is a waste of 25 bucks when a paper clip does the exact same thing as said code reader

 

[Zero Signal]

Common dude, anyone serious enough to be on this board asking questions on HOW TO... should own a code reader!!!

Yeah I know, but I don't like the beeping ones and the digital one I want is about $200. Anyway, I scanned it and got lean condition codes for both banks as well as a faulty egr, but I'm not sure to what degree that can increase the temp, and it still doesn't adress the issue with the fan not coming on by temp. I'm gonna get a guy at work to scan it with his gigadollar diagnostic equipment I think on Friday and see what it spits out. I'm still convinced it's a fan issue since I ran around all day today with the A/C on and the needle never exceeded the 'O'.

 

[baskin]

There are three pieces involved in engaging the high speed circuit: The pcm, the ccrm, and the fan itself. Start with fan. Disconnect the fan from the ccrm, connect the high speed input to the battery positive, and ground the negative input to the fan. If the fan runs, reconnect the fan and check the ccrm by grounding pin 17 on the input of the ccrm. If the fan runs, the pcm is defective.

 

[94GTLaserRC]

anyone serious enough to ask how to should know that a code reader is a waste of 25 bucks when a paper clip does the exact same thing as said code reader

Um what about "wasting" money on a screwdriver when a butter knife works..

OR, you can find a rock lying around the yard and use it as a hammer. .

Oh yeah, and why spend all this money on our Mustangs when you can get a rechargeable 10MPH motor scooter for $199...

Seriously, the code reader is a GREAT investment!!!
RC

 

[jmuva44]

See if you can relate to this...

http://forums.stangnet.com/showthread.php?t=439687

As you can see, I had a similar problem and replaced many things. Turned out to be a darned $15 sensor. Who knew?!?!

Chris

 

[Zero Signal]

Yeah I just replaced the sensor last semster, but I ran a gigadallor scan tool on it today and noticed the ECT voltage was going nutz, the temp would jump around randomly from 60° to 210°. I looked at the sensor and saw the wires were frayed then unplugged it to find the thing all wet inside! That's what I get for going with the cheapo off-brand replacement!

Anyway, since I work for the city, I just went straight to Ford and ordered a new factory sensor and repair harness for about $53 total. I'll put it in on monday and see if it works out. Hopefully it will kick on the fan. ANd with the computer being able to refer to the right timing and fuel tables, I'm hoping for alittle more power and better cold performance.