[99duxburyrr]

I know EAS problems are pretty well documented on this forum, but I couldn't find one with my symptoms. Hopefully someone has seen this before.

I noticed the front sitting a little low in the morning, more so now that it is winter here in New England. No obvious leaks, so I figured it was in the valve block and I would rebuild it at some point. But then the compressor stopped working, and the up arrrow and all of the lights on the indicator were lit but no fault was indicated. I checked all the functions through the connector at the EAS and the thermal switch is ok (12 volts across pin 1 and pin 16), the compressor pumps up the system when pin #8 is energized, readings at the the pressure cutoff showed it was functioning (12volts across pin 13 and pin 18), but the compressor didn't won't work on its own. I lifted the car up through the solenoids using jumpers and let the car sit with the EAS all hooked up overnight. This morning, the front was down a little but when I started the car and shut the door, it leveled itself. The up arrow is still lit, the level indicator lights are all on, and the compressor never came on. The valve block seems to be working, as are the height sensors if it levels itself but it won't activate the compressor. The dash now shows EAS fault, but it isn't a hard fault.

I'm a little baffled. Could there be a fault that prevents the ECU from activating the compressor?

 

[John W]

If it is a soft fault,then AFAIK when the ignition is turned off and later turned on again the system does a test and some soft faults can be be reset by the system.
If it is a hard fault then the system will have to be connected via the OBD port to a device capable of resetting the fault. :think:

 

[Keijo]

Hello 99duxburyrr,

Reading 12V at pin 13 (P/Sw output) to pin 18 (Ground) at the connector, indicates to the ECU that the system is at full pressure.

RAVE, is very clear on this, the pressure switch contact will be in position [1], ie, 12V at pin 13, when the pressure is above 10 Bar
That means it is switching the compressor OFF.
You need to read 0V there for the compressor to be actuated!

It looks like your pressure switch is not changing state when the pressure drops.

Cheers,
Keijo

 

[TheoR]

Another simple thing that's gonna prevent the compressor from starting up is your compressor relay. Why don't you switch it up and see what happens. I've had the similar symptom of the up arrow (high mode) going with a stuck relay. In my case, it was the opposite effect of where the compressor kept pumping air into the system, causing the height to go much, much higher than normal.

 

[99duxburyrr]

I guess i need to clarify my initial post a little bit. I measured 0 volts across pins 13 and 18 until I ran the compressor for approximately 15 minutes, at which point I measured 12 volts indicating that the pressure cutoff had been activated. I had to jump pins 1 and 8 to run the compressor initially, so it was not activated by the low pressure in the sytem even though the cutoff switch was open.

I checked the solenoids before I pulled the EAS ECU plug and it looked fine but I swapped some around anyeway to no avail. Sending 12 volts to Pin 8 actually energizes the coil on the relay which then sends power to the compressor so the relay is good.

I am in the process of making up a harness to plug in my laptop to see if I can make any headway from that direction. Serial cables are pretty rare these days, but I have that end worked out. I may have to use the pin approach on the OBD connector side for now, though. Fortunately the connector in the Rangie is in the perfect place for this approach (not).