funky gauges

[2002wX]

every time i put my jeep in 4wd the gauges go nuts the seccond i hit the gass. it will say im doing 80 when im doing 10 and the feul gauge ethier goes all the way down or all the way up. the tach works fine but every thing else go nuts and eventully goes dead. does any one know what causes this and does it ever happen to any of you??:

[jay79cj7]

Sounds like you have a short somewhere. What kind of Jeep do you have?

[Bounty__Hunter]

Now that's a strange problem indeed. So for the problem to happen, you have to 1) be in 4wd, and 2) accelerate?
It doesn't happen during acceleration in 2wd?

Ya, what year and model jeep is this?

[2002wX]

its a 2002 wrangler X and no it only happens in 4wd not in 2wd

[Junkpile]

Unplug the wire for the four wheel drive light and see if it still happens. That is a VERY strange problem. Let us know what it turns out to be.

[jps4jeep]

ok, the new electronic speedo's are great huh. might be a issue of a bad resistor (I think that how the new chryslers speedo work.) if it is a 2002, it should be under warranty still.

[XJNick]

If it only happens when in 4x4, then it does sound like either a short or an open ground in the 4x4 light circuit. You'll probably want to remove the dash and inspect the connectors to make sure somethings not frying back there.

Keep in mind that the gauges are driven through the Powertrain Control Module (PCM) over the CCD Bus (twisted pair wiring), so anything affecting the PCM's CCD bus outputs or wiring will cause lots of problems.

By the way, my fuel gauge on my TJ always randomly zeros out if the fuel level drops below like 1/4 tank of gas. I've gotten used to it though

-Nick

[fourtrail]

The new speedometers work on an electronic pickup that triggers everytime the trigger point on the output shat passes it. Then the computer converts the output rpm to milage after figuring in tire size and gear ratio. Lots of resistors, just not that simple. As to the fuel gauge, that problem is common on chrystler products. My 95 ram would bounce around at 3/4 tank. the problem is a bad spot in the sending unit at that level of gas.. loosing contact. As for the wrangler, like others said remove the wire from the switch at the t-case and see what it does.

[BostonJeep]

call an exorcist

[2002wX]

thanx it was a short

[XJNick]

Hey, where was the short circuit? I'm always interested to know what the solution was to an electrical problem

-Nick