Alright I have asked a couple members, but we are all at a loss.

I installed my EATC, but I am having some serious problems with it. For instance the problems I am having is as follows:
- fan runs on high when the HU is shut off and blows it out the defrost vents
- fan has 2 speeds when the HU is on, high and medium
- the a/c wont engage (i think it might be either bad clutches or compressor)

Here is what I have done:
- replaced the Fan Speed Controller
- checked, checked, checked, checked, checked, did i mention that i checked the wiring

All the wiring is correct according to John Grigg's (n3elz) How-To on his Car Domain ( http://www.cardomain.com/ride/296394/14 ). My blend door motor works perfectly, it fell right in when i installed it.

Does anyone know what MIGHT be the problem When i disconnect the Y/BLK wire from the R/O wire, all the fan power stops......

Any help would be great!

 

What is the red/orange wired to under the hood? How many pins does the new relay have?

 

the R/O wire under the hood went to my factory Fan Speed Controller, at least that is the only place i know of it going.....by the way John's How-To talks.......

are you talking about the relay i added to control the a/c with the "rear fan off" switch? if so, it is a SP/DT relay.....

or are you talking about the new Fan Speed Controller? it had 2 larger, and 3 smaller pins...

 

The red/orange that was at the original resistor plug should be unused and taped off.

The orange/black (or orange) at the FSC should go directly to the orange/black of he blower motor and no where else.

FSC brown/orange goes to head unit brown/orange via the truck's orange/black.

FSC white/pink goes to HU white/pink via the truck's light green/white.

FSC tan/orange goes to HU tan/orange via the truck's yellow/red.

FSC black goes to chassis ground.

 

that is exactly how i have it.....the R/O wire at the FSC has a butt connector on it and then taped off.......all the other wires is exactly how i have them wired.....

 

Which pin of the head unit is wired to pin 85 of the relay that you added?

Which pin of the head unit is wired to the truck's yellow/red?

 

both on the "white" connector
85 = Pin 22 (R/O0 (circuit 260)
Y/R = Pin 10 (T/O) (circuit 184)

 

That sounds right.

 

Maurice, is the EATC you installed the correct one for this mod? I ask that because Ford makes several EATCs that look alike but the internal circuitry is different between them. When you plug the wrong one in (at least on an SHO), symptoms arise that are very similar to those you have posted.

 

hmmmmm.....

any other ideas Bob? i am at a loss here bad.......

When i disconnect the Y/BLK wire from the R/O wire, the fan doesn't blow at all.....

For some reason, the HU is now reading *C instead of *F like it did last night also.....i have the solid red wire tapped into the 12v switched wire....

 

i got the whole setup from Frank (pastfinder), he said every componet came out of a '99 Explorer....

 

If it has a green display and "Rear Fan Off" pushbutton, then it should be the right one for the wiring he is using.


I have the 97 Ranger and 99 Explorer Wiring Diagrams here and I'm looking at those along with John's How-to. I've been trying to find instances where it would be easy to make a wiring error but haven't found anything wrong with what you've done.

 

Maurice, did you bench test the system before the install?

 

no

i am leaning toward a bad HU, but everything seems to work properly.....

i installed a brand new FSC today, so i know that isn't the problem....
the blend door works properly.....
the EATC HU doesn't show any error messages when i do a self test.......

i am totally at a loss.....

 

I guess that leaves open the possibility of a bad HU in addition to everything else. Given the compexity of the installation and all the variations possible between the different year combinations, my first guess was that it was just a crossed wire somewhere. Now I'm not so sure.

 

Have you pulled the HU to check it/clean it? It checked out fine when I pulled it and didn't have any indication of damage to it. Did you clean the contacts on the wheel as I suggested?

 

They did... I pulled the entire unit out of a 99 Eddie Bauer edition Explorer and the HU and interior sensor had not been exposed to any rain.

 

wouldn't the self test give a code if it was a bad HU? everything else works flawlessly.....how would i tell if i have a bad HU?

 

no i haven't done that yet, but that wouldn't let the fan blow after the whole unit was shut off would it?

 

Honestly I don't know. It shouldn't.

 

when i shut the HU off, i put my volt meter on the Y/BLK wire and there is like 1.5v coming off of it.....is that suspsosed to be that way or is the Y/BLK wire only susposed to supply power when the HU is on?

 

It appears that the HU grounds the yellow/black to activate the blower relay. That's all I know about it.

 

by the way this says from John's How-to

does that mean that the relay that i have wired for the "rear fan off" switch to operate the a/c compressor (relay with the purple wires)? or did i miss another relay in the wiring? because it says this directly under the above quote:

 

so what does the R/O wire that is in my trucks wiring harness do? is it a constant ground or is it a hot wire? from the sound of Grigg's How-to when he says to tape and insulate the R/O wire under the hood by the FSC, he calls it a "dual friction" wire....

 

i have tried all the other relay options but this 1, do you think it would be worth a shot to try this way: