Topic: Second guessing the fan controller...

[sharpxmen]

splice, solder and shrink tube on that wire

[Jeffy]

I'm trying to keep splices to a minimum though.  It's a lot easier to get to one terminal and add a Y-harness in there anyway.

[dwtaylorpdx]

Did you use the AC line that auto-bumps the idle when the AC is on to trigger the fan? then it only comes on with the compressor.
Its the single wire in the middle of the firewall. (At least it is on my 94... But my factory system does not use it, Its tied in to a harness under the dash.

Cheers.

Dave'

[Jeffy]

Did you use the AC line that auto-bumps the idle when the AC is on to trigger the fan? then it only comes on with the compressor.
Its the single wire in the middle of the firewall. (At least it is on my 94... But my factory system does not use it, Its tied in to a harness under the dash.

Cheers.

Dave'

Nope.  The FSM shows the AC request turns on when the blower fan is on.  Not when the clutch comes on.  There is no engine fan trigger as the engine uses a mechanical fan.

The stuff you're missing was discussed in this thread. http://4bangerjp.com/forums/index.php/topic,2783.705.html

[dwtaylorpdx]

HUh,, I'll be darned. Mine only high idles with the compressor on...  The plug that runs mine is in the engine compartment... with a short harness through the firewall to the ac control panel...  Mine was a dealer installed unit. But I did have serious issues with the dealer later.

I've been hoping for the score on a yard pullout from a Hemi pickup... :)

Dave

 

[Jeffy]

HUh,, I'll be darned. Mine only high idles with the compressor on...  The plug that runs mine is in the engine compartment... with a short harness through the firewall to the ac control panel...  Mine was a dealer installed unit. But I did have serious issues with the dealer later.

I've been hoping for the score on a yard pullout from a Hemi pickup... :)

Dave

 

Yeah, Sharp also mentioned just hooking the AC Request and fan to the clutch.  I'm not sure if one way is better then the other.  Does the PCM bump the idle up in time or is there a slight shudder?  Really though using the clutch trigger would be easier.

[dwtaylorpdx]

Min maintains the engine speed + a few rpm, if the pump switches off there is a momentary bump to like 950 rpms if there is no load on the motor.

I've found it helps keep speed up when crawling along in L-L :0 and keeps me cool! Bonus.


Dave

[Jeffy]

Min maintains the engine speed + a few rpm, if the pump switches off there is a momentary bump to like 950 rpms if there is no load on the motor.

I've found it helps keep speed up when crawling along in L-L :0 and keeps me cool! Bonus.


Dave

So it compensates quick enough not to drop below 750 when the pump kicks in?  I forget are you using an electric fan or the engine?

From a performance standpoint it would probably be better if the idle up and the fan only turn on when the compressor is on.  If I was to do that I'd need to splice the clutch signal in too places.  One for the AC Request and again for the fan.

[sharpxmen]

HUh,, I'll be darned. Mine only high idles with the compressor on...  The plug that runs mine is in the engine compartment... with a short harness through the firewall to the ac control panel...  Mine was a dealer installed unit. But I did have serious issues with the dealer later.

I've been hoping for the score on a yard pullout from a Hemi pickup... :)

Dave

 

there are 2 wires that go to the PCM, A/C request and A/C select, one tells the PCM that you turned the ac on, the other one tells when to high idle while the compressor is on - that's how Jeffy will wire it.

there's also an a/c relay ground coming from the pcm, most likely as a safety feature so it can turn off a/c if engine temp goes too high.

[Jeffy]

there are 2 wires that go to the PCM, A/C request and A/C select, one tells the PCM that you turned the ac on, the other one tells when to high idle while the compressor is on - that's how Jeffy will wire it.

there's also an a/c relay ground coming from the pcm, most likely as a safety feature so it can turn off a/c if engine temp goes too high.

I thought one was to turn the clutch on and off and wasn't connected to the high idle?  Gonna have to look at that again.

I ended up redoing the Y-harness.  I swapped the cable from 14awg down to 16awg since I found some scraps.  (I have a lot of wire.)  Turned out better then I though.

[sharpxmen]

looks good, just use 2 shrink tube strips on the dual connection side that cover the diodes and then a larger one over everything so it keeps it nice and straight.

I thought one was to turn the clutch on and off and wasn't connected to the high idle?  Gonna have to look at that again.

there is one that goes to the thermocouple/thermostat inside the evaporator and from there to the pressure protect switch on the canister, if i'm not mistaking from there it goes to the clutch. So the compressor will only operate when those 2 contacts are closed, so should the high/normal idle select.

[Jeffy]

looks good, just use 2 shrink tube strips on the dual connection side that cover the diodes and then a larger one over everything so it keeps it nice and straight.

That's the plan.

I'm now thinking I might have the fan turn on with the clutch instead.  I don't really want it running 24/7 and the bullet connectors are easy to get to.

Looks like I can get to the A/C Select at the PDC and tap in there with a blade terminal.  I'm wondering if I'll get to the A/C request this year though.  Running out of time this year.

[sharpxmen]

i updated my previous post with a comment on your pcm connections.

[Jeffy]

i updated my previous post with a comment on your pcm connections.

Ok, I'll check it out again.

I got antsy and found just enough shrink tubing to fit over the diodes.  I tend to use that size tubing a lot and only and 1" of it left.



And here it is sealed up.



 

[neale_rs]

Looks like a pro job!