Intermittent start issue and no power to a/c clutch

[BlindViper]

Based on what you described, it should be working...

Assuming...if the relay clicks when ACC_CMD changes state, there's nothing wrong with the control circuit. If connecting the "green" terminal of the socket to power engages the clutch, not much left to be a problem except the relay itself or it's socket contacts.

I have tried multiple relays in the fuse panel and no change. Could you check what the control voltage is in yours? Gonna check Friday when I get home and see if the control voltage is changing when the a/c is turned off/on. Gonna order a new relay as well.

 

[BlindViper]

Based on what you described, it should be working...

Assuming...if the relay clicks when ACC_CMD changes state, there's nothing wrong with the control circuit. If connecting the "green" terminal of the socket to power engages the clutch, not much left to be a problem except the relay itself or it's socket contacts.

I have tried multiple relays in the fuse panel and no change. Could you check what the control voltage is in yours? Gonna check Friday when I get home and see if the control voltage is changing when the a/c is turned off/on. Gonna order a new relay.

 

[ProjectSHO89]

What you referred to as a "control voltage" is an active ground that the PCM supplies to the "low" side of the coil when it is to be commanded "on". You cannot simply pull the relay out and measure it though, it doesn't work that way and you'll get readings that are not valid. Either the relay must be present or something needs to be connected across the coil's socket terminals to allow the circuit to function. An incandescent lamp (12V bulb) for example, would work.

 

[BlindViper]

What you referred to as a "control voltage" is an active ground that the PCM supplies to the "low" side of the coil when it is to be commanded "on". You cannot simply pull the relay out and measure it though, it doesn't work that way and you'll get readings that are not valid. Either the relay must be present or something needs to be connected across the coil's socket terminals to allow the circuit to function. An incandescent lamp (12V bulb) for example, would work.

The relay doesn't click when cycling on/off of the climate control system. If I remove the relay it definitely clicks as I plug it back in. A/c on or off.

 

[ProjectSHO89]

Good, a clear and explicit answer. The relay's momentary clicking upon insertion is likely immaterial.

I'd diagnose as a open circuit in the relay control signal, either in the wiring, internal to the PCM , or a poor/bad connection at either end of the signal line.

Ignition off.
Disconnect connector C175B from the PCM.
Inspect pin 12 on both connectors for any evidence of corrosion, bent or retracted male pin, stretched female pin or anything else out of the ordinary.

If visual reveals nothing of consequence, perform a resistance check from harness connector pin 12 to AC Clutch Relay socket pin 1 (you labeled it as a blue dot in your photo). Should read zero ohms, manual says less than 5. Give the harness at both ends a good flex and wiggle test to check for any intermittent connections.

If nothing notable is found, it's likely an internal PCM failure.

 

[BlindViper]

Good, a clear and explicit answer. The relay's momentary clicking upon insertion is likely immaterial.

I'd diagnose as a open circuit in the relay control signal, either in the wiring, internal to the PCM , or a poor/bad connection at either end of the signal line.

Ignition off.
Disconnect connector C175B from the PCM.
Inspect pin 12 on both connectors for any evidence of corrosion, bent or retracted male pin, stretched female pin or anything else out of the ordinary.

If visual reveals nothing of consequence, perform a resistance check from harness connector pin 12 to AC Clutch Relay socket pin 1 (you labeled it as a blue dot in your photo). Should read zero ohms, manual says less than 5. Give the harness at both ends a good flex and wiggle test to check for any intermittent connections.

If nothing notable is found, it's likely an internal PCM failure.

View attachment 342834

Excellent info! Thank you!!!

 

[BlindViper]

Excellent info! Thank you!!!

Good, a clear and explicit answer. The relay's momentary clicking upon insertion is likely immaterial.

I'd diagnose as a open circuit in the relay control signal, either in the wiring, internal to the PCM , or a poor/bad connection at either end of the signal line.

Ignition off.
Disconnect connector C175B from the PCM.
Inspect pin 12 on both connectors for any evidence of corrosion, bent or retracted male pin, stretched female pin or anything else out of the ordinary.

If visual reveals nothing of consequence, perform a resistance check from harness connector pin 12 to AC Clutch Relay socket pin 1 (you labeled it as a blue dot in your photo). Should read zero ohms, manual says less than 5. Give the harness at both ends a good flex and wiggle test to check for any intermittent connections.

If nothing notable is found, it's likely an internal PCM failure.

View attachment 342834

Is the pcm and ecu the same?

 

[BlindViper]

Good, a clear and explicit answer. The relay's momentary clicking upon insertion is likely immaterial.

I'd diagnose as a open circuit in the relay control signal, either in the wiring, internal to the PCM , or a poor/bad connection at either end of the signal line.

Ignition off.
Disconnect connector C175B from the PCM.
Inspect pin 12 on both connectors for any evidence of corrosion, bent or retracted male pin, stretched female pin or anything else out of the ordinary.

If visual reveals nothing of consequence, perform a resistance check from harness connector pin 12 to AC Clutch Relay socket pin 1 (you labeled it as a blue dot in your photo). Should read zero ohms, manual says less than 5. Give the harness at both ends a good flex and wiggle test to check for any intermittent connections.

If nothing notable is found, it's likely an internal PCM failure.

So I finally got to get it apart. Connector is actually the center one on the pcm not the far right or left that could be implied by the picture. I got .4 ohms from the connector to the relay. I removed all the connectors and sprayed them down with electrical contact cleaner. Put it back together and its working. Now I don't know what fixed it and it probably will return again next year. At which point there maybe fire involved. Thank you very much for the help!!!

 

[ProjectSHO89]

Probably some corrosion on the mating pins that caused them to lose contact, maybe the pins were just stretched and loose.

Keep your comp insurance bill paid...

 

[texsn95]

Nvm