Not sure how to test the RH sensors. Not sure if you can. The thing with the 7v vs. the 12v has me concerned also. I am not sure what it really is supposed to be. Most computers do not provide 12vdc output, and with the relay having a dedicated 12vdc source, it makes sense to me that the output from the computer would be between 5-7v. All that signal is going to do is "open / close" (can not remember if these relays are Normally Open or Closed contacts) the relay contact, thus completing the 12v power to the compressor.

If I remember, I will check and see what voltage I get on the smaller wires when I get home and will post back here with the info.

I would not count out the sensors yet. They provide a signal to the LLs module as to when to raise / stop / lower the system. You can have a bad sensor and still raise the vehicle by manually providing power to the compressor, thus bypassing the module. Let me ask, when you manually raised the vehicle by powering the compressor, did it stop on its own when it got to height or did you have to stop it by removing the power source?

 

Bummer. Would hate to buy one only to find out that isn't what is causing the problem.

I agree. However, the HELM manual seems to imply that there is 12v going to the module. For example, on page 14-1 it soes that Fuse 4/15amp comin out of the power distribution box goes to the Air Suspension Service Switch. That switch either shunts to nowhere (if turned "off", breaking the circuit) or (if ON) completes the circuit into pins 1 and 21 on the Air Suspension Module. Furthermore, Pin 4 is shown as coming thru the fuse/relay panel into pin 4, and is only hot @ 12v (run) which means when the truck is running.

Thus, it isn't out of the realm of possibility that the module can supply a 12v signal to a relay. That same page shows a switch on pin 18 which shunts to ground. My assumption is the switch is closed (no voltage) when the computer doesn't want to run the compressor, and opens (proving voltage) when it does, to trip the relay.

Thanks, that would be helpful and would supportwhat I should expect to see when I go home in an hour.

I've never seen the front of the truck change height, only the rear. The front appears to be fully inflated. I assume I have a small leak in the rear which causes the truck to lower over the course of a week. If I pump it manually, it appears to stop "at height", although I also couldn't say with any certainty I know what "at height" is really supposed to be.

Regards,
Vinny

 

Put an ohm meter across the ride height sensor and move it throughout it's travel, see if the resistance varies as the travel of the sensor changes.

 

Problem solved!

The problem was with the relay connector.

Apparently, the 'A' wire totally corroded inside the connector and disintegrated. I discovered this when I tested for 12vdc on the A pin. no voltage.

There's a little "cap" on the connector. I popped the cap off, and pulled on each wire. The A wire came right out! It was severely corroded.

By the time I figured this out, it was well after 12 when the parts dept at my dealership closed. So I picked up a few "crimp" blade connectors at the auto parts store, removed the old connector, and then put on 4 crimp connectors.

I reconnected the 4 crimp connectors. Eureka! The air suspension works again!

Total time to fix: 1 hour

No other connector showed signs of significant deterioration (B showed a little but not much). I guess the high current coupled with the poor position of the relay means it picks up a lot of road salt and eventually oxidizes.

Thanks everyone for your help! this forum is great!

 

Oh, and as it turns out, I didn't need the relay either. My old relay was okay. My old compressor is ok. I can resell the compressor on Ebay and make my money back.

Again, thanks everyone for saving me $625 at the Stealership. Amazing they would have charged me for a compressor and probably charged me for the wiring harness too saying I needed both!

I'm glad I didn't listen to that other dude who said go back to the dealership!

My out-of-pocket expense: $75 diagnostic fee at the dealership (waste of money) $120 for the relay (which turns out I didn't need), $4 for the crimp connectors, $0 for the replacement compressor (I figure the compressor I can sell for what I paid, so that'll be a wash or maybe I might "lose" $20 on the deal) --- $229 total

Actual cost to repair had I come to this forum first: $4

Savings thanks to everyone here: Priceless


I wonder if I can dispute the $75 diagnostic fee on my credit card

 

Now, Q. Did you by chance test the voltage across the connections coming from the module? I got home too late last might to test mine and was gone all day today. Just wondering, that way we can put the 12v vs 5~7v thing to rest.

 

I wish I would Have seen this thread sooner, as I know a guy who sells all the stuff dirt cheap and is highly educated on how it works and will always help his customers until they find the issue. For future reference of those who experience these types of problems, the link is

http://www.americanairsuspension.com

and he has a great deal on all the parts at

http://www.americanairsuspension.com/1-2-1-deal.htm

 

OK - I am having the same problem as Tentpig did. (99 Navigator) My question is - is this relay and connector setup located directly under the air-box? I think that is what I am looking for. I also could not identify the air union described near the master cylinder. Does anyone have a picture? I would rather take the engine completely out rather take my Navigator to the dealer!
Any help is greatly appreciated.
KS

 

Here is a diagram, its kinda crappy but the only one I can find on alldata

 

I now have the same problem. My check suspension light is on. My air compressor works, I disconnected the wire to the relay and hard wired Pin A and Pin B and the compressor worked.
When the compressor works both the front and the rear is lifted so my front is very high and my rear is just about right.

 

Hey guys, where is the relay? the module?

 

ok. yesterday i got a new relay from Ford and my suspension is back to normal now . The relay is behind the front bumber on the driver side. I found mine just close to the horns.

Also the new relay I got from ford has a different part number already than the original. Guy from the dealer says its normal for Ford to change part numbers.

Some information I noticed regarding the relay.

1. Both the new and broken relay I got I can't measure the resistance from pins C and D.

2. When my Check Suspension light is "ON" the voltage I'm getting from pins "C" and "D" is 3.2 volts.

3. I checked the relay by applying 7 volts to pins "C" and "D" and check if pins "A" and "B" closes. If it does then the relay is working if it is not then it's broken.

Workaround I did:
My LLS broke on Dec. 24 so no Dealers where open and I can't get the relay until Dec 29 and I needed my gator working because its the holiday season and we have a lot of relatives visiting us. What I did is to remove the relay, buy a 3-4 meter wire put a switch in on end, on the other end connected to wires which was connected to pin A and B (thick wires) of the relay. I ran the wires into the drivers seat so I can manually turn on/off the switch for the air compressor I acting both as the driver and the air compressor relay Be careful not to overinflate though.

The module is inside the dash.

 

Problem I had --> Front Sensor bad
Symptons --> Check suspension light, no air compressor sound.

Actions taken --> Read this forum. Tested relay but became confused and wound up replaceing relay.

Observations --> Pin C and D voltages ( before front height sensor replaced and problem solved )
1. key on = 7.5 volts ( with the bad sensor)
2. air switch by passenger off = 12 volts.
3. After replacing height sensor and turning on switch 12 volts. Air compressor pumps.

A measurement of less than 12 volts between CD must mean the computer is in a "wait state" looking for data from the height sensor.

 

Hi, this thread has been very helpful to me. So, here's my situation (I share as others may be in the same pickle). I have a new-to-me 1998 Navigator, 5.4L, all factory, with air suspension.

Initially, my compressor never comes on and the rear is sitting awfully low (makes for a horribly bouncy ride). So, following the thread I hooked up a by-pass for the compressor; when I apply 12V battery voltage to the compressor (key in ignition, ignition turned to start (but not actually running), doors closed, then the compressor comes on and the front would pump up, but not the rear.

Following air lines, I found the union (under the master cylinder) had blown: Bought an air line union from NAPA (3/16", metal, $8), cut new ends to the air lines, stripped about 1/2" of the black from each end of the air lines, plugged the white ends into the new union, and now I have air going to the rear. Manually pump it up again, but after a few hours, the rear is sitting low again.

More reading and research led me to the following: Using the by-pass procedure, I pump up the front and the rear ends manually. Then I turned the air suspension system OFF, using the on/off switch in the passenger leg room area. 4 hours later, my passenger side is still inflated, but the driver's side is sitting low. So, now I know that there is an air leak and it's located in the rear driver side.

I mixed up a spray bottle of soapy water (joy and water), crawled under the rear driver side of my Navigator, and started spraying the air shock and solenoid of the air shock. For me, it was instantly obvious that the leak is in the area of my solenoid.

Now for my question: I see there are rebuilt solenoids and rebuild kits for solenoids on the web. But how do you actually remove/install the solenoid. There must be something holding it in location or the air pressure would pop it out.

I've looked and looked on the web, and the only thing I can find is talk about some retaining clip and twisting the solenoid (to release air) and twisting again to remove. Rather vague stuff. Does anyone have a picture of the retaining clip? And twist how (clockwise, counterclockwise, no difference)? Thanks in advance.

I don't even want to address the problem of why the air suspension isn't working automatically yet, I just want it to hold air when I manually pump it up (for now -- actually, I think the failure of the auto-suspension is a blessing in disguise; otherwise, with such a large air leak, the compressor would run excessively and eventually burn itself out).

 

What I'm thinking is why u didn't get the Monroe LLs-standard suspention conversion kit for 230$ and less if u look right and no more guessing what's wrong with your truck