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-   -   more EATC help...... (https://www.ranger-forums.com/general-technical-electrical-18/more-eatc-help-43281/)

lifted97ranger 05-14-2007 06:52 PM

more EATC help......
 
alright......i thought i had everything together and installed on my EATC, but now for some reason my A/C wont work.......

before i installed the EATC, it worked like a dream....i just had it serviced and all new seals put in it......

alright, i have 12v power at BOTH electrical connections at the compressor.....i just put on a brand new clutch, pulley, and coil.......when i jump a wire from the battery to the clutch coil, it engages the clutch, but when the plug is pluged in, the coil wont engage.........the compressor is free and turns........i have tried to by-pass the safety switch and it still wont engage......

if i read the EATC How-To instructions properly, the Y/BLK wire from the EATC HU is susposed to go to the R/O wire in the trucks wiring harness to engage the A/C relay......i was told that it would show 0v when the A/C was selected to be on, and it would read 13v when the A/C was off.......it is reading 13v both times............

anyone know what i could try besides a new compressor....i think i just went and spent $85 on a new clutch and didn't need it.....

any help would be great....

V8 Level II 05-14-2007 07:46 PM

Deleted

lifted97ranger 05-14-2007 08:00 PM

thanks bob......i will try that tomorrow when i get off work.......hopefully that is all it is....

V8 Level II 05-14-2007 08:26 PM

Deleted

lifted97ranger 05-14-2007 08:29 PM

Quote:

Originally Posted by rwenzing
I think that if you are seeing ~12v on both sides of the clutch it means that the ground is disconnected somewhere. Having 12v on both sides means that there is 0v potential across the clutch and that isn't going to do anything.

The ground side should always be ~0v with respect to chassis ground.
The hot side should be ~12v wrt chassis ground when the clutch is commanded.

whenever i stick both of my voltmeter leads into the plug that goes to the clutch i see 12v.......i didn't mean to say i had 12v on both sides.......sorry for the confusion.......

i also have 12v on the electrical plug on the back of the compressor........

V8 Level II 05-14-2007 09:20 PM

Quote:

Originally Posted by lifted97ranger
if i read the EATC How-To instructions properly, the Y/BLK wire from the EATC HU is susposed to go to the R/O wire in the trucks wiring harness to engage the A/C relay......i was told that it would show 0v when the A/C was selected to be on, and it would read 13v when the A/C was off.......it is reading 13v both times............

The EATC yellow/black to the truck's red/orange is how the EATC tells the HVAC blower motor that it is OK to operate. It has nothing to do with the compressor clutch.

For 2000-back like yours, the purple wire controls the clutch directly. There are a series of switches that all must be closed for the power to get from the purple wire to the compressor clutch solenoid. However, you are seeing 12v difference across the clutch solenoid, so that all appears to be working. It also means that the clutch should be operating.

lifted97ranger 05-15-2007 08:50 AM

Quote:

Originally Posted by rwenzing
Deleted

why did you delete that:shrug: i was going to try that when i got home....

lifted97ranger 05-15-2007 08:51 AM

Quote:

Originally Posted by rwenzing
The EATC yellow/black to the truck's red/orange is how the EATC tells the HVAC blower motor that it is OK to operate. It has nothing to do with the compressor clutch.

For 2000-back like yours, the purple wire controls the clutch directly. There are a series of switches that all must be closed for the power to get from the purple wire to the compressor clutch solenoid. However, you are seeing 12v difference across the clutch solenoid, so that all appears to be working. It also means that the clutch should be operating.

could it be a bad A/C relay? it sounded like it was chattering when i opened the power distribution box under the hood......could that do it?

you would think that the clutch would be operating.....espically since i have put power from the battery to it directly and it engages......

V8 Level II 05-15-2007 09:05 AM

Quote:

Originally Posted by lifted97ranger
you would think that the clutch would be operating.....espically since i have put power from the battery to it directly and it engages......

This is what is confusing me. Basically, you're saying that putting ~12v across the clutch from the battery makes it operate but ~12v across the clutch from the harness does not. How can that be?

V8 Level II 05-15-2007 09:10 AM

Quote:

Originally Posted by lifted97ranger
why did you delete that:shrug: i was going to try that when i got home....

Because it was based on the idea that you had 12v on both sides of the clutch connector. However, in a later post, you corrected that to say that there is a 12v difference between the 2 wires.

So, I saw it as no longer relevant and deleted it to avoid confusion.

lifted97ranger 05-15-2007 09:11 AM

Quote:

Originally Posted by rwenzing
Because it was based on the idea that you had 12v on both sides of the clutch connector. However, in a later post, you corrected that to say that there is a 12v difference between the 2 wires.

So, I saw it as no longer relevant and deleted it to avoid confusion.

ahhhh ok i understand now! sorry....

lifted97ranger 05-15-2007 09:13 AM

Quote:

Originally Posted by rwenzing
This is what is confusing me. Basically, you're saying that putting ~12v across the clutch from the battery makes it operate but ~12v across the clutch from the harness does not. How can that be?

i dunno.....doesn't make sense to me! i will double check it when i get home, and i will put a meter on each side of the plug to double check.....

this a/c thing is bothering the piss out of me.....

could the compressory be bad.....and how would i tell if it was bad?

V8 Level II 05-15-2007 09:17 AM

Quote:

Originally Posted by lifted97ranger
could the compressory be bad.....and how would i tell if it was bad?

It doesn't matter if it's good or bad if the clutch can't engage to drive it. You need to resolve that before throwing any more parts at it.

lifted97ranger 05-15-2007 09:19 AM

Quote:

Originally Posted by rwenzing
It doesn't matter if it's good or bad if the clutch can't engage to drive it. You need to resolve that before throwing any more parts at it.

ahhh true that.....

could it be a bad A/C relay? it sounded like it was chattering when i opened the power distribution box under the hood......could that do it?

V8 Level II 05-15-2007 09:28 AM

Quote:

Originally Posted by lifted97ranger
could it be a bad A/C relay? it sounded like it was chattering when i opened the power distribution box under the hood......could that do it?

There is a WOT cutout relay on your 97 that must be closed for the clutch solenoid to get voltage. If the relay is chattering, it is either a bad relay or there is a wiring error somewhere. You could try swapping it temporarily with an identical relay in the box. That should tell you if the relay is at fault or not.

lifted97ranger 05-15-2007 09:31 AM

Quote:

Originally Posted by rwenzing
There is a WOT cutout relay on your 97 that must be closed for the clutch solenoid to get voltage. If the relay is chattering, it is either a bad relay or there is a wiring error somewhere. You could try swapping it temporarily with an identical relay in the box. That should tell you if the relay is at fault or not.

alright i will try swaping that out.......it looks to be a SPDT relay......

would you know were the wiring error could be by chance?

V8 Level II 05-15-2007 09:34 AM

Quote:

Originally Posted by lifted97ranger
would you know were the wiring error could be by chance?

Can say because I can't see it.

lifted97ranger 05-15-2007 09:37 AM

Quote:

Originally Posted by rwenzing
Can say because I can't see it.

true that......man i wish you lived closer :sad:

what gets me is the efan and everything else comes on like it is susposed to when the HU demands a/c....

Rockledge 05-15-2007 08:59 PM

Bob, in looking over the relevant '97 wiring diagram I was wondering something: could a blown A/C clutch diode either affect or prevent proper clutch operation?

V8 Level II 05-15-2007 09:29 PM

Quote:

Originally Posted by Rockledge
Bob, in looking over the relevant '97 wiring diagram I was wondering something: could a blown A/C clutch diode either affect or prevent proper clutch operation?

I'm no expert but I don't think so. Here's the way I see it. If it's shorted, it will take out the fuse. If it's open, it will just pour a bunch of current into the circuit every time the coil field collapses. That's not a good thing (arcing) but the clutch should still function, at least in the short term.

Rockledge 05-15-2007 10:03 PM

I follow you (I think). As far as you can tell, the diode is there essentially just to protect the rest of the circuit when the clutch coil field collapses. It does not have a role in execution of the circuit (i.e., clutch engagement).

lifted97ranger 05-15-2007 10:59 PM

i pluged the connector in and then jumped a + wire off the battery to the B/Y wire and the clutch engaged.......i also OHM'd out my ground wire from the clutch to the chassie ground and it was good.......so that at least means it is a power problem right:shrug:

lifted97ranger 05-15-2007 11:00 PM

i also swapped out the A/C WOT relay with a like SPDT relay and it still didn't do anything different...

V8 Level II 05-16-2007 05:45 AM

Quote:

Originally Posted by Rockledge
I follow you (I think). As far as you can tell, the diode is there essentially just to protect the rest of the circuit when the clutch coil field collapses. It does not have a role in execution of the circuit (i.e., clutch engagement).

Yes, I think it provides a circular path to allow for the dissipation of the induced current to protect the WOT relay and other switches from excessive arcing.

V8 Level II 05-16-2007 05:53 AM

Quote:

Originally Posted by lifted97ranger
i pluged the connector in and then jumped a + wire off the battery to the B/Y wire and the clutch engaged.......i also OHM'd out my ground wire from the clutch to the chassie ground and it was good.......so that at least means it is a power problem right:shrug:

If it engaged when you jumped B+ to the black/yellow and it doesn't engage otherwise, then there must not be any voltage present on the black/yellow from the clutch control circuit. However, I'm sure that you said there is 12v across the compressor clutch coil from that circuit with the A/C on. How can both be true?


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