Help- Bizare abs and speedo issues, replaced dif sensor

[Dragonlich1961]

i've got a 2000 ford ranger 2.3 5 speed basemodel. truck is stock.
Couple weeks ago, it stated haveing a few issues. Abs light kicked on, and speedo acted weird. It is fine on acceleration but anytime you hit the brakes, even if only enough to trigger the brake switch, the speedometer pegs to zero.

i've replaced the rear dif sensor, and it is still acting up.
the speedometer also seams to resond to the turnsignal activation, and is now off calibration on aceleration. like 15 over off calibration.

The truck is not in my posision at this time. It's my gf's and im 7hrs away at college. i work on it when i get a chance to get home so, this might take a while.

Thaks Chris. this Truck was abused before i came into posesion, i mean abused. 185k i've had to rebuild front suspension with bj's bearings rotors. Pulled off orginal shocks(4) plugs wires and clutch at 180K.

 

[RonD]

If you have 4 wheel ABS then problem could be in the ABS module

If just rear ABS, which is most likely on base model, then GEM module process's the VSS sensor signal, adjusts it for tire size and passes that on to the speedometer, cruise control, computer and RearABS

GEM module also has brake light switch input.

So could be GEM module issue.

when speedo stops, brake lights on, does odometer also stop?
they share the same signal
so issue could just be speedometer
but then ABS light would not be on

 

[Dragonlich1961]

Where would this Gem module be located and how do i test it.

what does the gem module do excatly?
one more symtom I have been told exists, i have not experienced this yet, When ever the abs light is on, normal braking happens. when the abs light is off it seams that the pedal get hard and won't travel any farther.

I 'm trying my best to get this thing working and to provide as much info as i can but the truck is 300 miles away and i can only visit ocasionally while at college

Thanks, chris

 

[RonD]

No way to test a GEM as far as I know.
GEM(general electronic module) replaced several separate relays and modules

It's parameters are here: http://www.explorerforum.com/forums/showthread.php?p=1725290

What it controls is specific to the vehicles factory options.

Usual location is behind the radio, not sure on a 2000 2.3l

Last symptom reads like power booster is not working at times, which is not an electronic part so ABS light or GEM couldn't effect it.

 

[Dragonlich1961]

i've replaced the booster once this whole deal started becuased i noticed a whoosing noise on pedal depression. still doen't explain how it's tied to the abs light. new booster fixed the noise but speedo, abs and physical brake problem still exist.

I have no idea when to locate this GEM module i'll start looking

Chris

 

[RonD]

Did you set the new power boosters push rod to match master's piston?

It needs to be adjusted so there is no slop and piston can come back all the way

read here: http://www.jegs.com/installationinstructions/500/555/555-631010-116.pdf

 

[enjr44]

The GEM was doing a bunch of weird stuff on my GD's 02. Locking/unlocking doors when turned the key to on or off, intermittent wipers coming on by themselves, just weird stuff. Anyway, battery was really old (11 yrs and just around 12v when sitting). Disconnected battery for about an hour while getting a new one. After replacing the battery all the weird GEM stuff stopped. That was over 2 yrs ago.

Just saying........... No clue about your truck.