GOT-Torque
is
- Joined
- Jul 2, 2007
- Messages
- 5,284
Finally went to the dealer and had the A/C system recharged in the Excursion. We couldn't get the clutch to kick in. With the two switches jumped (high pressure drop out switch) and the switch mounted on the cylinder tank by the firewall (can't think of what it's called at the moment) had no power at the clutch.
Looking in the wiring manuals, it should have been engaged with the controls set to A/C. So I pulled the relay in the fuse box and jumped 12V there to engage the clutch and charge the A/C. According to the book, the ford ECM grounds a pin to energize this relay (which for some reason it isn't working).
So here's the question, does the ECM kick the compressor on and off based upon the system pressure or does the ECM turn it on continuously based on the control switch and the high pressure switch kicks the compressor off and on?
I'm assuming since the high pressure switch doesn't feed back to the ECM it must control disengaging the clutch based on high pressure on it's own and the ECM just reads the control switch position to power the clutch (given the pressure switch hasn't dropped out).
?
Looking in the wiring manuals, it should have been engaged with the controls set to A/C. So I pulled the relay in the fuse box and jumped 12V there to engage the clutch and charge the A/C. According to the book, the ford ECM grounds a pin to energize this relay (which for some reason it isn't working).
So here's the question, does the ECM kick the compressor on and off based upon the system pressure or does the ECM turn it on continuously based on the control switch and the high pressure switch kicks the compressor off and on?
I'm assuming since the high pressure switch doesn't feed back to the ECM it must control disengaging the clutch based on high pressure on it's own and the ECM just reads the control switch position to power the clutch (given the pressure switch hasn't dropped out).
?
