When I plug the top connection into the Gem module the fuse blows. What's my first step? And does anyone have a wiring schematic for the F57B-14B205-EM
im not that good with a multimeter or vehicles but I got all the time in the world.


Gem module 1995 smells a little burnt

Speedometer odometer windshield wipers engine light really need that last one

 

Welcome to the forum

So fuse 25 in the Cab fuse box, it has 12volts all the time not key on power
And it is OK with GEM unplugged, it also powers instrument cluster full time?

If it only blows after GEM is plugged back in then issue is for sure inside the GEM

You can open up the GEM and look for any corrosion or "discolored" areas
Brush off the board, could be a loose piece of solder is shorting out something
Ford never released schematics for these as far as I know

I just have Ranger diagrams but Mazda should be the same.......I think
You have a 4x4 GEM so I assume a 4x4 B4000

Part number is F57B-14B205-EM

If no obvious internal damage then replacement GEM will be only option

Good place to look here: https://www.car-part.com/

1995
Mazda Pickup B-4000
"part" Computer Box Not Engine
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GEM in this case is called Multifunction
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1996 models should work as well as 1995
Looks to be about $70 + shipping, they are light and not larger so are easy/cheap to ship

 

The fuse is a 7.5 in the truck not a 10 amp. The colors on the wires are different also I think.

 

I don't have Mazda diagrams but the fuse panels are Ford so each 1995 Ranger/B-series fuse functions should be the same, wire colors can be different

This is a 1995 Mazda EVTM which will have the correct diagrams and colors: https://www.ebay.com/itm/16618827316...3ABFBM1NSMiNBi

These are usually free to use, as you can resell them for what you paid, just like the person selling this one is doing

 

Can't I just clip a wire and plug it back in with one less thing? And not blow the fuse.

 

Not sure what you mean?
If you clip the wire from the fuse at the GEM, then GEM loses that 12v source, and if you plug it back in and fuse no longer blows then yes, the GEM was the short, but some GEM functions will no longer work, and not sure what those would be

 

I mad all those connections individually and none of them by them self blew the fuse?

 

That is odd

Not sure where to go on that, one of the device's 12v wire socket should be close to 0 ohms to ground to blow the fuse
Could be a chaffed wire in a harness that is grounding out enough to increase amp draw, test each 12v wire, with fuse out, should be no connection to ground at all