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

[sandmanxx]

REF: A/C issues

So is there really a PTC#1 somewhere "inside/under/other location" on the IPM on a 2004.5 truck.

I read somewhere its a "flash/scanner" thing.. ??

On another note I hate having to think about a flash it a dealer. Causing other issues..
I have a smarty and clear codes myself.. (just a random side note)

 

[Bob4x4]

The 04-05 trucks do not have a tipm.there are a pdc(fuse box) and the fcm (front control module).

 

[sandmanxx]

First - thanks for the rely.

But I know we dont' have a TIPM.. The wiring says a PTC! Are you saying it's the same thing

 

[Bob4x4]

PDC is the fuse box power distribution center. PTC positive temperature coeficient-some reset some dont.In the case of the tipm the A/c will recover in most cases in the pdc models I do not recall seeing that happen

OPERATION

The A/C compressor clutch relay is an electromechanical switch that uses a low current input from the powertrain control module (PCM) or engine control module (ECM) depending on engine application, to control the high current output to the compressor clutch electromagnetic coil. The movable common feed contact point is held against the fixed normally closed contact point by spring pressure. When the relay coil is energized, an electromagnetic field is produced by the coil windings. This electromagnetic field draws the movable relay contact point away from the fixed normally closed contact point, and holds it against the fixed normally open contact point. When the relay coil is de-energized, spring pressure returns the movable contact point back against the fixed normally closed contact point. The resistor or diode is connected in parallel with the relay coil in the relay, and helps to dissipate voltage spikes and electromagnetic interference that can be generated as the electromagnetic field of the relay coil collapses.

The A/C compressor clutch relay terminals are connected to the vehicle electrical system through a receptacle in the integrated power module (IPM). The inputs and outputs of the A/C compressor clutch relay include:

The common feed terminal (30) receives a battery current input from a fuse in the IPM through a fused B(+) circuit at all times.
The coil ground terminal (86) receives a ground input from the PCM/ECM through the A/C compressor clutch relay control circuit only when the PCM/ECM electronically pulls the control circuit to ground.
The coil battery terminal (85) receives a battery current input from PTC 1 in the IPM through a fused ignition switch output (run) circuit only when the ignition switch is in the On position.
The normally open terminal (87) provides a battery current output to the compressor clutch coil through the A/C compressor clutch relay output circuit only when the A/C compressor clutch relay coil is energized.
The normally closed terminal (87A) is not connected to any circuit in this application, but provides a battery current output only when the A/C compressor clutch relay coil is de-energized.
Refer to the appropriate wiring information for diagnosis and testing of the micro-relay and for complete HVAC wiring diagrams.

 

[Bob4x4]

The ptc you are referring to is on the control side not the powerside of the relay-not a typical failure in my experience,but it could fail in theory

 

[sandmanxx]

Thanks.. Part of the problem is a lot note this - BUT - no one can tell me exactly where it is!

I just want to know exactly where it is "one of my check off items" .. I have the wiring diagrams and have been checking out the ac relay and
compressor / etc..

I have seen a lot of post talk of it. But on one states or show any pix of it.. It's the elusive PTC

 

[Bob4x4]

It should be in the pdc.If you are willing and able to take it apart look below the relay it will be on the pin 85 leg of the relay(downstream somewhere)

 

[sandmanxx]

I was just going to type a note..

Thanks . MORE IMPORTANTLY - I will post a note tuesday or weds with what I have done / checked..

Basically I put in complete new ac system and can't seem to get new compressor to kick in.. Pulled the system down to 350 microns and started to charge
the system, but the compressor would not kick in. Prob got 1.5 cans in.

Then started looking around online and on truck.

New compressor clutch engages when isolated
line from relay to "harness" connector reads a few ohms.
But when I "plug in" compressor to harness and check pin #87 to frame grounding I get 95.0 + ohm
Relay in compressor does not work
#30 get 12V
relay out and try to jump #87 to #30 I get nothing
* put in new harness side compressor connector for electric fan connection

As I "was" messing" with fuse box by moving/pulling it when trying to get washer bottle back in I am going to do the following:

Pull battery out so I have better access to the PCM and disconnect the mass connectors one at a time and clean with CRC electrical
cleaner and reset them.
Fix the 2 heater grid grounding bolts (not bolted)
Pull dash heater panel and check connectors
See if temp sensor is in
All above just because!

** insert not sure if dash panel is totaling working so I need to check panel. and look and make sure I don't issues there as well.. I took out HVAC and
don't remember even looking at connectors for heater unit..

 

[PWong]

PTC = Positive Temp Coefficient current limiting device.
It's like a resistor whose resistance would increase as the temp increase.
It functioned like a fuse for over current protection.
It should be on the electronic board.
If it's open and you don't want to fix it on the board then you can just replace it with a 5A fuse outside the board.
B+ power to 5A fuse then to A/C Clutch Relay pin 85.

 

[PWong]

Try these:
Key on, remove A/C Clutch Relay, check for B+ at pin 85. If yes then PTC #1 is good. If no then PTC #1 is open.
Check for B+ at pin 30. B+ comes from fuse #16.
With clutch connector plugged in, jump B+ from pin 30 to pin 87 to see if the clutch engage. If yes then the clutch and wiring are good. You have issue on relay or the ECM control signal.
Install a good relay.
Engine Idling, A/C on and blower on, go behind the IPM, locate the DB/OR wire on connector C5 behind the IPM.
Connect a 12V test light to B+ battery post. Probe the DB/OR wire.
Is the test light illuminated? If yes then the ECM control signal is good.
The test light would be OFF when A/C OFF.

 

[PWong]

http://www.rambodybuilder.com/2004/docs/wd/drwd/8W-42/8W-42-7.pdf

 

[PWong]

when I "plug in" compressor to harness and check pin #87 to frame grounding I get 95.0 + ohm
It should read the resistance of the clutch coil which was about 3 - 6 ohms.
#30 get 12V
relay out and try to jump #87 to #30 I get nothing
If you jump B+ to pin 87 and clutch failed to engage then something wrong with the wiring from pin 87 to clutch or the clutch itself.
Try jump B+ directly to the coil of the clutch (with connector plugged in) to see if the clutch engage.

Forget about the PTC now!!!

 

[sandmanxx]

Thanks PWWong

I will report back in a few hours.. But first I must admit my battery cable connections are questionable and I was in process of making new battery cable set
with bolt on leads/etc.. My stock ones are loose and positive comes off and negative isn't the best.. So as a temp thing I am cutting the stock lead connector gap so
the bolts can bolt down and get a "tight/secure" clamp.

Then continue with checking the ac.

Reason is yes I have gotten the code of P2509 ... The loss of power down data while engine running. May try to reset system. Hopefully I haven't fried something

just a FYI

 

[sandmanxx]

PWONG

You mean LB/OR #11 on C5 (ac clutch ..)

* there ia no DB/OR??

just a note on this one - I will check it last after everything else..

 

[PWong]

PWONG

You mean LB/OR #11 on C5 (ac clutch ..)

* there ia no DB/OR??

just a note on this one - I will check it last after everything else..

Yes.
It's the same wire, according to wiring diagram.

 

[sandmanxx]

Well I will have to do my list trmw and check things over again. I fixed the battery cables - much much better :--)

Going to make a short list / and check again / as I "handled" a lot of cables today!

As for checking the PTC I get a few millivolts with key on lol. Well recheck trmw.

When you state check ( B+ ) to xxxx (I assume you mean run wire directly from + battery terminal to point in question ?? )

 

[PWong]

When you state check ( B+ ) to xxxx (I assume you mean run wire directly from + battery terminal to point in question ?? )

Check with a voltmeter to see if there is battery voltage there.
The other operation was to jump a battery voltage to a point with a jumper, to test something.

 

[sandmanxx]

Mr Pwong Sir!

PIN 85 (key off / relay out) 12+ volts
PIN 85 (key on / relay out) nothing real lol

PIN30 ( key off / no relay) 12V
pin 30 ( key on / no rely ) nothing real lol

Jump 87 to 30 gets nothing
as for behind IPM I need to say *&#*^)!* and do it ..

Checked a few lines of the diagnostic procedure for the P0646.. (key on / not running / no relay - what I did) Checking voltage of fused battery supply and of course not good! It says to repair the
"open fused battery supply" ?? Exactly what / where? (I assume they mean to check voltage at the fused battery supply at the PIN on rely lol) I don't get within
1 volt of battery... I get nothing cry cry!

Exactly what do they mean when they say "repair the open fused battery supply" when checking

 

[PWong]

PIN 85 (key off / relay out) 12+ volts
PIN 85 (key on / relay out) nothing real lol
Try with engine idling.
Also try with engine idling and relay in.
If nothing then PTC#1 was opened.

PIN30 ( key off / no relay) 12V
pin 30 ( key on / no rely ) nothing real lol
Try with engine idling.
If nothing check fuse # 16 for open circuit.

Jump 87 to 30 gets nothing
Because there was nothing on 30.

Checked a few lines of the diagnostic procedure for the P0646.. (key on / not running / no relay - what I did) Checking voltage of fused battery supply and of course not good! It says to repair the
"open fused battery supply" ?? Exactly what / where? (I assume they mean to check voltage at the fused battery supply at the PIN on rely lol) I don't get within
1 volt of battery... I get nothing cry cry!

Exactly what do they mean when they say "repair the open fused battery supply" when checking
Usually check/replace the fuse and wiring for that circuit.
Fused battery supply = a battery supply protected with a fuse.
So there would be wiring and fuse involved.

 

[PWong]

Mr Pwong Sir!

PIN 85 (key off / relay out) 12+ volts
PIN 85 (key on / relay out) nothing real lol

PIN30 ( key off / no relay) 12V
pin 30 ( key on / no rely ) nothing real lol

Just wondering how that happened.
There were voltage when key off and there were no voltage when key on???

How did you hook up the voltmeter to measure the voltage, between which two points???