I purchased my 2000 F150 last June at the dealership & after about 2 weeks I noticed that when it rains I get clicking under the dash below the steering wheel. The airbag light flickers on & off with the engine stopped, & the blower motor runs with the key off & out of the ignition switch. I have also noticed when driving in the rain, my wipers will only work at whatever selected speed I originally set them at when I was in park. They won't shut off or increase speed until I go into neutral while driving or when I'm in park again. I took my truck back to the dealer the 1st time and they said they replaced two relays where I was hearing the clicking under the dash. About a month later this started all over again, took it back to the dealer and after keeping the truck for the day they said they could not find the problem except that I had water getting in somewhere. They said until I found where the water was getting in they would not be able to help me.
I would appreciate if someone could help me with this. I also posted this at other forums so if I find a solution I will post it to help others get this annoying problem resolved.

Thanks in advance. P.Brooks

 

Sorry to hear that you are having the same problem that I just got fixed after much frustration. Mine truck is a 2002 F150 Lariat. First, let me tell you that water is the problem. Your windshield seal is the most likely culprit. My windshield was not installed properly during manufacture and I didn't catch it until just before the warranty expired. The windshield seal is going to have to be replaced before the dealership will do any more work. Now the bad news, the windshield will most likely be broken as it is taken out, costing you around $260.00 to replace.

Then, ask the dealership to check out the main computer control module for water damage. It is located directly behind that relay that you keep hearing. It's under the dash to the left of the steering wheel. Mine was full of water and the contacts corroded. The lowest contacts in the module are the defrost fan and the interior lights. Kinda explains some things now, huh?

Anyway, after my first visit to the dealer at around 35,900 miles with electrical problems, I was talked into an extended warranty. Now at 75,000 miles with a new computer module, I'm glad I bought it.

Now the really bad news... The module and labor is around $1700.00 at the dealership.

As a very temporary solution, don't get the truck wet, and if you do to the point where it is acting up, leave it running with the heat set to the floor on high for a few hours. The heater will dry it out some, maybe enough to get you home without the interior lights flashing and all the air coming out of the defroster.

Best of luck.....

 

GEM/Central Junction Box is what I have been calling the main computer module. (found this in another post)

 

ssgar is right on the money. Uncle Henry's known about the windshield thing since about 1998 when Navigators and Expeditions first started having these concerns. The windshield typically leaks along the upper corner on the driver's side.

$1700 seems a bit high though...if you were really inclined, you could just have the windshield resealed and buy the GEM/CJB from your friendly neighborhood stealership yourself. IIRC, it shouldn't be no more than about $4-500 for them both. You have to do some crawling and creeping under your dash to get the GEM/CJB out, but it's nothing someone with some hand tools and a little patience can't get done.

After it rains again, wiggle fuses in the fuse box and look for arcs or sparks. Or, get some compressed air in a can and blow it into the fuse box, see if water comes out.

 

Well, if this is the case, the first thing I will do is have the windshield checked out. Once this has been taken care of and has proven itself to be the fault, I will go back to the dealership with my results of the leakage to see if they hold true to their word for the electrical fix. (Unlikely)
Thank you for taking the time in replying to this, it is very much appreciated.

P.Brooks