I took a couple of wires and plugged in the compressor directly to the battery through the two larger wires in the wire harness.

Yes, I think that only one of these actually is used for the compressor. Okay I just pulled them and they have a C8705 I believe on the side, the code is warn a little. When I found them just were just right behind the passenger light but don't know where they were mounted since I had it at a mechanic shop and he couldn't figure out the problem tell me he thought it might be my compressor.

 

It shows 12V 30A on the side of it and it doesn't look aluminum but black plastic and it looks like they were once mounted to something since they have a mounting clip on the edge with a hole for a bolt to go through.

 

I believe the 1999 Expy used a four 'prong' relay. (I don't have a 1999 here to verify), but I believe it should be the same as the F3LB-2C013-BA relay on my Navigator. (The finned portion of the aluminum ribbed heat sink is about 1" X 2" and the whole relay is about 2" X 2.5" X 1" thick.)

 

Well I just pulled a picture of that relay online and what I was referring to does not look like that. Makes me wonder if I have the wrong part. As far as having 4 prongs this one has a 5th one in the middle but it doesn't actually touch metal since the center of the harness does not have metal in it.

 

Is this relay hard to get to? Do you access it from under the vehicle?

 

Okay. What I'm thinking is you took two wires and attached them to the battery and the other ends of the wires you connected to the connector at the compressor (you did not connect them to the connector where the relay plugs in - right?) and the compressor ran.

Are you saying that you found the relays by the passenger headlight under the hood? Or by the passenger headlight from under the truck?

The compressor relay is accessed from under the truck, not from under the hood.

From where I'm sitting (here in Central New York State ), my SWAG (thats a Silly Wild A$$ Guess) would be your not looking at the correct relay, and the old relay has a cooked contact that was feeding insufficient voltage to your old compressor and burned it out. This same old relay is doing the same thing to your new compressor - that's why you hear the new compressor "ticking" and "clicking" as it burns out.

Can you find a relay from under the truck, between the right front wheel and the front bumper, about as far up as you can reach while laying on your back?

 

Dude you were right. I did not have the correct relay. I found it mounted where I thought the other relays were mounted. My problem was I couldn't recognized the relay because it did not look like a relay similar to what is in the cab or under the hood. So now my dilemma is do I really want to spend the $130 plus tax at ford to guess this is the problem. I did see a little "green" one of the larger wires but it wasn't crazy bad. Should I bypass this relay by crossing the two larger wires to test if it it is this relay?

 

No. First unplug the relay and go back to post #15 above and see what you have for voltage.

Then look inside the relay where the harness plugs in to it and you should see the pins marked A,B,C, & D. Jumper the wiring harness side of the connector between the equivalent of A and B (which should be the light blue w/pink stripe wire and the grey w/red stripe wire). If the compressor turns on its more than likely the relay that is keeping the pump from running. It is pretty rare for the low voltage side of the relay control circuit to have a problem.

 

The voltage matched what was at the battery. I jumped A & B and the pump ran. So maybe it's the relay then which is what I have read on here from others.

Guess I'm going to have to spend the $$ and get it fixed. I have it for sale since I purchased a 2011 F250 Super Duty and don't want someone else to have the problem so need to get it fix right.

 

It's too bad you are so far away. I have several spare relays in my collection of stuff. I have only had one of those relays go bad on my cars and trucks.

 

Our problems might be related. I replaced the relay on mine and the compressor still won't turn on. Upon further inspection of the harness/relay I noticed that the plastic around one of the plugs on the wire harness that plugs into the relay has melted slightly around one of the prongs. This might be my issue. My question is can I get this plug? Where? and what would it be called. Thanks to all!!

 

You will most likely have to get the plug from a J/Y. Your problrm is most likeiy the circut breaker that is soldered into the compressor housing that is not easily replaced. Will the compressor start if you jump the circut with a hot wire from the battery? If not the circut breaker ot a broken con rod is possibly the problem. Call American Air Suspension for a compressor with a 2 year warrantee.

 

Around one of the plugs? Do you have more than one plug?

Which prong was melted? (The relay's prongs should be labeled A, B, C, or D.)

Try to track down the cause of the melt down or you new plug may also melt down.

 

Thanks for the help. I am very pleased to announce it working like a champ again. I noticed the relay had a lot of corrosion on it so don't know if I really needed to replay the relay after all but it's done and working and am not taking it back off to test it.