1999 Ford Expedition - Answered Questions & Fixed issues

The GEM is located under the dash, on driver's side, on the back side of the fuse panel. If under the dash, upside down (or not), the GEM is located on the door kick panel side of the brake pedal, against the back side of the fuse panel, behind the under-dash fuse panel. The pin-out of the GEM is available in the Ford Factory wiring diagram manual which you find available for purchase on Ebay, or which you can find electronic versions available for purchase on eBay as well. (There is no free .PDF that I have ever seen.) All that is available is the pinout. The internals of the GEM module are not disclosed by Ford, and no technicians or dealers have the information (only Ford Engineering knows the internals, the unit is treated as a black box and cannot be service because of the lack of internals information.) The GEM malfunctioning (old) can be responsible for Window operation problems (as can many other things), windshield wiper operation problems (but also usually you steering column stem, or the two plastic connectors in the steering column that connect to the stem base), or the 4x4 operation (as the GEM runs the step motor and looks at the 4x4 switch input). Also, on '99 & 2000/1/2 Expy's, the GEM also takes the ABS wheel outputs, and refactors a "VSS" input the speedometer.

A cable to do what ... I wonder.

Dont be so fast changing the pump, when it was just the lines on mine. $15 at Walmart.com.

most likely not

The emission hose routing diagram should be on a 3" x 5" sticker either on the underside of the hood or on the top of the radiator support or on the air cleaner housing cover. It's kind of a symbolic diagram but will indicate what goes where. There are very few vacuum lines on one of these so it should be pretty straight forward.

horn relay (located in the battery junction box [BJB]).thanks

Any codes?

Cycle the switch by your passenger wheel well (inside the car). Mine did the same thing after not driving for 4 months with the battery drained. In noticed the rear was lower than it should be. Once I turned the switch off then on, it leveled up.

Is the car parked or running?

You may want to remove the cover over the wiper nut and tighten it down. Make sure you don't exceed the torque settings. The nuts have a tendency to back off causing the wipers (or one wiper) to slip.

Check the door locks take off the trim panel on the doors and go to the latch at the back of each door and check that the wire is connected and that it's clean this is a ground when the door is opened the interior lights come when you close the door they shut off if the wire attached to the locking latch in each door is broken or corroded or unplugged they can fall off the lights inside will stay on it only takes 1 bad wire for this to happen also check to see if you door pin switches when you open the door by the hinges on the frame about halfway up you'll see a pin or button like switch on all doors again one bad one is all you need and the running board lights are probably on the same circuit oh yeah there's a tailgate latch to and or a pin switch so take off all panels and look for the bad wire and in the frames where the doors close in the front and back doors those pins are in the front part of the body where the door post are the rear tailgate it's in the frame on the side near the top to stop draining the battery till you find it take out the interior light fuse for over night parking

Ford calls this the "GEM" It is to the left of the brake pedal arm under the dash. It is just a matter of a few fastners to remove.

Not enough transmission fluid in the tranny, Pressure regulator malfunction, reverse solenoid sticking or the transmission control module is bad.

I suggest you try one of those instant download manuals. My brother ( a mechanic) buys it when he can't fix some technical issue He buys from www.reliable-store.com . A lot of mechanics actually do this. Website is very good for this. Must try it !!

Sounds as though the signal relay (cube sized) switch has failed, this is normally located under the steering console once you have removed the cover panel.. I do hope this helps....

The IAC wouldn't cause a noise like you describe, and as for the spark plugs, it is possible but only if the plug broke off, or blew out of the engine. You say engine is running OK but a V8 can do that on 7 cylinders. Also you may be describing the beginning of a piston rod knock. You will need to check further. Good Luck Friend

intermittent wiper relay problem. see here.... https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-intermittent-wiper-relay

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Does it smell like rotten eggs ?

Car key have chip in it? Need more info, make model year.