04-21-2012, 06:37 AM
Compression Ignition Addict
Join Date: Feb 2008
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GEM modules get wet and freak
Below courtesy of Auto Parts Cheaper
So your dealer or mechanic has told you that you need a gem module to repair your vehicle. So now what? Your first question is what the heck is a GEM module? A GEM module is a General Electronic Module. Sometimes you will see it called a Generic Electronic module, or body control module. For the price of these modules, you would think you are buying a box of diamonds, or other precious gems, unfortunately this is not the case, Sorry!
What does a GEM Do?
A GEM controls all the basic functions of the interior electrical of the truck
Each configuration of a GEM on a vehicle can do many things, the most common things a GEM does is listed below, this is not an all-inclusive list, but includes the, most common options only:
Controls 4X4 on 4 wheel drive modes that have ESOF (knob on dash to control 4 wheel drive).
Supplies power to the radio.
controls power windows and locks
some modules include receivers for key less entry.
Controls Windshield wipers.
Controls Dome Light.
Those are just the basics, they do other things on different vehicles, there are over 180 combinations of options.
Where is it located?
In 1997-2001 Models it is bolted to the back of the interior fuse box. On 2002-2003 models it is on the back of the fuse box or behind the dash on the passenger side.
How Do I know if it is bad?
Unless you are a 5 star mechanic, don’t try to diagnose this yourself, you will go crazy and end up, at a bar, divorced and your soon to be ex-wife will have taken your dog with her. Seriously, it is near impossible to diagnose without the proper equipment, save yourself hours of your time and lots of headaches and just take it to a shop to be diagnosed, don’t be cheap on this one! We know a diagnostic fee sucks, but it will give you peace of mind knowing exactly what the problem is.
What makes a GEM Module Go Bad?
There are 2 things that make them go bad.
Most Common: The Ford Waterfall. Windshields in these trucks were manufactured with a bad seal. The seal shrinks over time and deteriorates letting a nice waterfall pour down right into your gem module and fuse box. Check for green corrosion on your connector pins, or inside the fuse box for evidence of this.
Semi Common: Your so lucky, your one of the very few lucky guys whose module just died on its own for absolutely no reason. Now don’t you feel special?
There are so many options, how would I ever know which one to buy?
Let us find it for you, call us at 281-416-4071, or if you are brave enough to find it on your own, go here.
Does my Module need to be programmed by a Ford Dealer?
For 1997-2001 Models the answer is no. IF you have a 2002 or 2003 model there is a slim chance you will need it programmed. If you have a 2002 or 2003 and you do require programming avoid the dealer at all costs, and have it programmed by and independent shop. Dealers hate when you bring your own parts, they will make any excuse as to why the part you brought it will not work, and try to trick you into buying their module at a much higher price. A good Idea is to avoid them all together, most of the larger shops have the correct equipment for programming, if you are calling around just ask them if they have the equipment to program ”as built codes” into GEM modules.
I have a 2002 or 2003 Model; will it have to be programmed for sure?
Probably not. There is about 5% of trucks that will require programming. Just install the gem module on your truck and most of the time everything will work correctly. IT will do no harm to plug in in unprogrammed. In a few rare instances there will be something that does not function. In that case you are one of the luckily ones who gets to go doe to the shop or dealer and have it programmed, Lucky you!
My Ford dealer says it does have to be programmed for my year model and it’s not a 2002 or 2003!
Your dealer is being dishonest with you. GEM modules manufactured between 1996- and 2001 do not have programmable chips in them, the equipment to program GEM modules was not even available until late 2001.
Last edited by ZMANN; 04-21-2012 at 06:41 AM.