Solved 98 Explorer No A/C

[Kendall]

Hi, Im Kendall and Ive been lurking here for a while.
My truck is a 98 Explorer Sport with 150 000 miles 4.0 SOHC.

My AC isnt working. More specifically the fan. I know the compressor works because when I go underneath the hood, there is condensation on the compressor and it is cold to the touch. The rear fan works fine. Also, since I bought the truck the fan would go to 1, 2, 3 but not 4. When you would turn the knob to four, the fan would shut off. Now, no air bows from the vents or the defrost vent.

I *think* the problem may lie in a vacuum leak or the blower motor resistor pack, but Im not sure how to troubleshoot these. Any help is greatly appreciated, and I know this is a great forum.

 

[TheJackal]

The first problem was the Fan High-Speed relay wasn't working.

Now, the resistor is also blown, so no fan action at all.

 

[Kendall]

Do you know where in the relay box this is? Or a ford Part Number? Thanks for the help.

 

[TheJackal]

The High Speed Relay is located in the Auxiliary Relay box, near the air filter box.

The blower motor resistor is mounted on the air plenum, under the hood between the blower motor and the evaporator case. You might need to move the cruise control solenoid to get to it.

You should be able to get the relay at any parts store. The blower resistor is a special part you will need to get from the dealer. When you go, make sure they ask you if you have the manual A/C controls (3 knobs) or digital A/C controls (EATC) as the parts are different.

 

[Kendall]

I know the relay is in the relay is in the distribution box, but I was wondering which one it is. The resister is under the cruise control, got it. But do you happen to have part numbers? Thanks again.

 

[scucci]

A relay diagram is in the owners manual. If you need it get it here:
Dead Link Removed

The blower resistor pack and hi relay are available at most auto parts stores.

 

[Kendall]

I replaced the relay, the ac still doesnt work. So im gonna go get the resistor pack from ford.

 

[TheJackal]

The relay for the blower is in the Auxiliary Box 1. Only the Battery Junction Box is diagrammed in the Owner's Manual. I think there's somewhere near 3 or 4 Auxiliary boxes, depending on the features you have.

Which relay did you replace?

 

[Kendall]

I replaced relay #9 in the power distribution box on the right side of the engine bay next to the battery. I wasnt aware there are other boxes. Where are they, and which relays should I replace? Thanks again for the help.

 

[TheJackal]

Relay Box #1 is near the airbox.

 

[Kendall]

Is it under the airbox? Ill try to get a picture of what I think it is tomorrow.

 

[Kendall]

I replaced the relay in the junction box under the air filter. Still no air from front vents or defroster on any fan speed or ac setting. Any other ideas? Thanks again.

 

[TheJackal]

In that case, you might want to test and see if the blower motor is getting power at all in any setting.

If it is, it could be the motor.

 

[Kendall]

Stupid question, but how would I do that? With an ohmmeter?

 

[rhauf]

Stupid question, but how would I do that? With an ohmmeter?

With a volt meter (should show at least 12 volts) or test light.

 

[Kendall]

Ok thanks. Ill have to borrow one.

 

[Kendall]

Replaced the resister, works perfectly. Though I couldnt get the screws on for the life of me. I was gonna let my girlfriends father(my mechanic) bolt it on for me, As I took it off so it wouldn't get damaged between now and tomorrow, the high speed still works, That hasn't worked since my brother bought the truck 3 years ago.

Thanks for all the help jackal.

 

[TheJackal]

Replaced the resister, works perfectly. Though I couldnt get the screws on for the life of me. I was gonna let my girlfriends father(my mechanic) bolt it on for me, As I took it off so it wouldn't get damaged between now and tomorrow, the high speed still works, That hasn't worked since my brother bought the truck 3 years ago.

Thanks for all the help jackal.

Good idea on taking it out if you can't mount it; it gets cooled by the air blowing across it.

You're welcome, I'm always glad to help. It's what ExplorerForum is about!

 

[rhauf]

Be sure the connectors on the plug (where the resistor thingie plugs into the wiring harness) are clean. if there is a bad connection there it will get hot, and cause the problem all over again.