So the IPM ( PTC #1 ) where exactly is it?? Can it be reset or changed??

[PWong]

have maybe 1.5 cans in. That should be enough.

I think so.
If NOT, you can ground C13 (LB/OR wire/pin 85) to test the relay circuits.
The relay should be energized.
Pin 30 would be making to pin 87 and send power to engage the clutch.

 

[sandmanxx]

You mean putting pin to socket 85 - to good frame ground - then if I hear clutch fire up truck and check gauges hanging

Also was thinking of running wire from pin 87 direct to connector at compressor ( with relay plugged in)

 

[PWong]

You mean putting pin to socket 85 - to good frame ground - then if I hear clutch fire up truck and check gauges hanging

Also was thinking of running wire from pin 87 direct to connector at compressor ( with relay plugged in)

With relay plugged in, gound pin 85 would energize the relay.
The Clutch connector was BAD.
Fix that or jump the two wires ( use two jumpers) on the connector.
Jump the power wire and jump the ground wire. Or just cut off the connector and connect the wires together.
The clutch should be engaged.
You are not running the compressor here since engine was not running.

 

[PWong]

You mean putting pin to socket 85 - to good frame ground - then if I hear clutch fire up truck and check gauges hanging

Also was thinking of running wire from pin 87 direct to connector at compressor ( with relay plugged in)

Don't jump pin 85 to gound if you want to run the compressor and check gauges.
Plug in the relay, engine running and turn ON the AC and blower.
ECM would ground pin 85 to energize the relay.

 

[sandmanxx]

Sorry didn't see your post #43

I was thinking the harness connection under the fuse box was the point that was bad..

First thing I did was put in a new "harness side" compressor connector.. Its not soldered up yet but..
Also checked the compressor connector and wire behind compressor connector and got 1 +/- ohms.

Its when I checked the wire up at the relay point to ground that I got 100 ohms..

** ANYWAY **

To keep it simple you are saying hard wire the compressor to the harness side to wires?? Correct.

Confused because I didn't think the issue was at that point.

I was thinking of hard wiring the relay contact pin with relay in to under fuse box wire?? Will this work?

 

[PWong]

As for pin 87 cable to compressor you make a point. I check the cable run from back side of fuse box to the harness side connector at compressor "ohms"
was basically 2 +/- ohms. Did not break that run down. Checked end to end.
So the wire from pin 87 up to harness connector was good.

Did check harness side ground at compressor and it was solid..
So the harness side ground was good.

I fired the clutch with it isolated and running a ground lead from the compressor connecter pin and clipping it to block - then battery 12V to connector hot pin!
So the clutch was good.

I then connected the compressor to harness wire and plugged the run back in to the fuse box..

Checked the 87 pin at relay (relay out) to ground and got 95 +/- ohms..
So the harness connector was defective!!!!!!!!!!!!!!

Can you confirm what you reported???
According what you reported the connector was BAD.
You got 95 ohms instead of 5-6 ohms.

 

[PWong]

With relay removed, on top of IPM, check resistance between pin 87 to ground.
You want it to be 5-6 ohms.
If it reads 100 ohms then the wiring from pin 87 to clutch connector to clutch coil then back to connector to ground BAD.

 

[sandmanxx]

HOLD THE FUSES - SO SORRY BUT AT SOME POINT THE RELAY DIAGRAM PINOUT I DRAW FROM THE PHYICAL RELAY GOT FLIP IN RELATION TO LOOKING DOWN AT RELAY
CONTACT POINTS. BASICALLY I HAD 30 and 86 and and 85 and 87 flipped.

Correct readings in a sec "as looking down at relay on board for correct board outputs

 

[PWong]

HOLD THE FUSES - SO SORRY BUT AT SOME POINT THE RELAY DIAGRAM PINOUT I DRAW FROM THE PHYICAL RELAY GOT FLIP IN RELATION TO LOOKING DOWN AT RELAY
CONTACT POINTS. BASICALLY I HAD 30 and 86 and and 85 and 87 flipped.

Correct readings in a sec "as looking down at relay on board for correct board outputs

OMG!!!!!!!!!!!:-laf:-laf:-laf

 

[sandmanxx]

12 volts at pin #30 key on /off

12 volts at 86 with key on~ Don't know what happened to key off lol..

 

[PWong]

12 volts at pin #30 key on /off
Great.
12 volts at 86 with key on~ Don't know what happened to key off
Great.
Should have nothing when key OFF

It looked great so far.

 

[PWong]

Jump 30 to 87 to see if clutch engage.

 

[sandmanxx]

Sorry out all day.. Will post up a correct list of findings and now since I have the pins correct can recheck part of the diag. code steps I did.

We will find right issue at hand #@$%!

I will post in AM around 11:00 - as I am working nights right now

 

[sandmanxx]

(relay out) Well didn't do much today but check ohms between 85 and 86 - is less then 100 ohms ( got 92 +/- ohms)

(rely out) key on. Checked fused battery supply voltage circuit in PDC / and battery voltage and they are with 1 voltage. ( No real difference)

Wednesday going to do following:

So going to check ECM C13 wire between ECM and PDC (ohms)
PDC C13 to negative battery (ohms)
do some other checks with pressure sensor ?? checking it's voltage and ground etc
other ??

 

[PWong]

(relay out) Well didn't do much today but check ohms between 85 and 86 - is less then 100 ohms ( got 92 +/- ohms)

(rely out) key on. Checked fused battery supply voltage circuit in PDC / and battery voltage and they are with 1 voltage. ( No real difference)

So the relay coil and PTC#1 were good.
We don't know about the contact between pin 30 and 87 of the relay yet until we actually energize the relay.

 

[sandmanxx]

Good Day Sir!

One problem right now is to check bottom side ECM cabling its a hell of a lot easier with tire off / wheel liner off. Having said that I am driving it also. I jumped to another task
to "get something" done.

I finally jumped the compressor by giving pin #87 12V + direct feed :-laf Charge system to +/- 30 oz of 134r. Now I know the compressor at least works when you force it too.
Can we say COLD, COLD. COLD air in those vents

Anyway I never really knew how hot the condenser gets at idle. Let me tell you at first (for a few milliseconds) I honestly thought something was really wrong
in the "closed AC system" .. Then I got the H20 turned on and was watering the condenser - turned up the idle an charged the system - after taking the H20 off the condenser
man did steam start coming up. Anyone would have thought my radiator cap / system is smoking lol.

Electric fans are a must to fix/tweak these systems correctly!

Back to my problem.

Checking voltage and ground issues in cab heater switch panel. The mirror and snowflake bottom does not come on. The fan/blower connection works and the instrument
panel lights and function all seem to work - and the new bulbs I put in the heater switch work.

Need to check the ECM wires between ECM and AC clutch relay.
Now that I have system charged I can see what voltage the pressure switch has and what the outbound voltage is.

Honestly I just wanted to change tracks an get other things which may hopefully bring me bac to the issue from the other side !

 

[PWong]

Checking voltage and ground issues in cab heater switch panel. The mirror and snowflake bottom does not come on.

Needs to fix this first. It's the A/C Control panel send out the "A/C Clutch Request" message to ECM.
After fixed (snow flake light On when you pushed the A/C button) this you can plug in the Clutch relay to see if the clutch come on.

Need to check the ECM wires between ECM and AC clutch relay.
If the clutch failed to come on then you need to check the A/C Clutch Control signal.

Fix the A/C Control panel first.

 

[sandmanxx]

You think reflashing the AC switch control head would help / "maybe" fix issue?? Or does the head really only control door motion.

Reason is I broke own and went by dealer to see about air bag recall fix.. Asked if he would hook scanner up and check AC control. Told him I basically had new AC system - now
charged - and was having issues with AC relay but it "seems" maybe be ok - and was looking at panel right now..

He point blank asked did I reflash the control head. Have I never reflashed?? I said not in 10 years - if it isn't broke don't fix it..

I may just have them do that and check to see if other issues. "Nothing else - do not fix/change anything" He agreed. I think I will ask to see the reflashing / check in person
just for FYI. The guy "seems" ok - he is a typical San Antonio older Mexican who has worked around cars forever.

But yea $110 to flash and check out system. Must say its a holiday weekend and he said if I can be there at 08:30 he can check it - other wise its next weds or Thursday.

I never really knew what they meant by AC control Head..

 

[sandmanxx]

Fixed

fixed

fixed

fixed

 

[sandmanxx]

FIXED !







I THINK..

Had a new heater switch in box waiting/in case needed. Me and my dad (99 years old) started talking about computer chips and memory chips
and 5 volt circuits. He was saying I have 12 volts at heater connecter - but maybe there is a 5 volt circuit on heater micro controller that you can't
check see.. Flash memory his thinking about.. Unless you break out a scope and / or other serious tools) ...

Anyway after checking ground and voltage for panel I decided to do a few things and pop in the new heater switch I had.. and guess what -
the mirror heater light started blinking - started truck - then closed my eyes and pressed the snowflake - it started snowing and out the AC vents!

Now have to cross fingers about all the new heater doors I put in.. Hope the modes work!