ARC Suspension woes - pls help me in identifying parts

[GEOFFERS]

After hooking up my caravan it soon dawned on me that the self levelling system wasn't working at all, I had my suspisions as the warning light would always come on after 20 mins of driving.

I have a spare ex for parts and thought that by changing the compressor over the problem would be solved.....Oh no, if only so simple...

I have trawled through the posts and I think the following is true:-

The level switch determines the height by operating two solenoid valves to either allow air to inflate or deflate the shocks.

The level switch also initiates the compressor if required but only if the dryer has reached temperature.....

right so far???

I have taken my car to bits and swapped the compressor assembly with a spare, but no change, still no running compressor, after removing the height sensor to simulate a rise and drop in ride height the solenoids operate but thats all.

Can someone put me right on a few things........The compressor assembly has two thinnish wires going to a metal block(dryer element??) and two thicker wires going to a metal cylinder (compressor???) with the air pipe emerging from a black plastic cylinder (dryer???)........have i got these right and can i test these on the bench.

sorry for the essay, now going to cool figers under the cold tap, looking forward to any help, ta

 

[Stenasev]

Can someone put me right on a few things........The compressor assembly has two thinnish wires going to a metal block(dryer element??) and two thicker wires going to a metal cylinder (compressor???) with the air pipe emerging from a black plastic cylinder (dryer???)........have i got these right and can i test these on the bench.

The two thick wires power the compressor to raise vehicle, the two thinner wires power the vent solenoid to lower vehicle. The air pipe emerges from the dryer.

Should be easy to bench test. I think the following colours are correct but please satisfy yourself that they are first!

Red - Compressor (+)
Black - Compressor (-)

Blue - Vent (+)
White - Vent (-)

Post back with test results!

SS

 

[CDW6212R]

It may just be a lack of power for the compressor. Check the two fuses in the PDB and relay under the hood. The compressor will be run off of one big fuse and one relay. The rest of the ARC runs off of the other small fuse in the Power Distribution Box. It may just be a lack of power for the compressor.

 

[DuncanOfEngland]

Geoffers,

The compressor (energised via a relay) and air switching valves are controlled by the ARC controller, which takes into account the desired ride height, actual ride height and other factors such as whether the load door is open. If the suspension does not reach the desired height within a certain time, then the dashboard warning lamp is illuminated.

You can test the compressor and and switching valves by energising them, but make sure that they are isolated from the car's electrics before you do. Apart from that, then you'd need to try point to point testing for the integrity of the electrical connections. If everything is good, then the most likely candidates are the ARC controller, the ARC relay or the ARC level sensor.

Duncan Clarke
Ford Explorer Services and Parts

 

[GEOFFERS]

Firstly thanks for the pointers!

I left my meter at work today and couldn't check for voltage, but....

I tested the compressor and solenoid valve which are working fine so it is a power issue somewhere, either losing the feed or ground connection to the compressor,or the relay isn't energising at all.

I think from reading some more posts (CDW6212R's from june 04!) the compressor relay is in the relay block under the air filter, does anyone know which of the relays it is? The relays in this block seem to be quite corroded so maybe this is where the fault is,

thanks again!

 

[CDW6212R]

Check the two fuses first, they should be easy to find with an owner's manual.

I can't help much with your relay, my entire system came from a 98 Limited, and there are big wiring changes from 98 to 99. Some relays moved around starting in 99. Mine was in a small two relay box very close to the master cylinder. In 1999 Ford did away with most of the separate relay boxes, except for the one under the air cleaner.

Check the owner's manual first, hopefully listed with the other relays it will tell you where to look for it. The power for the compressor comes from the frame wiring harness, which has a connector under the left front seat on the inner frame. That's very close to where the wires go up into the floor, into the body harness.

So that connector on the frame is an easy place to find and test for power, if you can trigger the relay. I'm suggesting once you find the relay, test it and if it's okay, test for power at the connector I just described. That wiring at the connector should have zero resistance back to the compressor.

 

[GEOFFERS]

Found it!

The fault was the relay connections, the switched feed had corroded off completely.

A bit of engineering/bodging and all is up and running again.............WAHOO

All I need to do now is put the car back together again lol

 

[CDW6212R]

Very good, where was that relay buried on your truck?

 

[GEOFFERS]

Don,

it was the bank of relays just under the airbox, first and largest , my Ex is a '98 model, the power comes off fuse 3 (40A) with the relay being energised from the module.

I googled electrical schematics and came up with some invaluable drawings although they may be for your LHD Ex's (not 100% sure though) as the drawings state relay locations etc but these sent me on a wild goose chase,

thanks again for your input,

Geoff

 

[CDW6212R]

Excellent Geoff, I know how Ford changes things often, and the RHD versions are much different. Those are often symmetrical, just things placed on the other side, so I knew it best to only generalize. You figured it out, well done.