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BS: Mechanic Advice Needed/Jeep

20 Nov 04 - 12:11 PM (#1333647)
Subject: BS: Mechanic Advice Needed/Jeep
From: Sorcha

Help! I know Mr is a mechanic, but this one has him stumped. The speedometer on my 96 Jeep Grand Cherokee is not working right. Sometimes it doesn't work at all, other times fine, others intermittently, and sometimes goes plumb crazy. We've changed the sensing/sending module and it didn't help....damn thing is electronic. Any bright Ideas? Thanks!


20 Nov 04 - 12:21 PM (#1333655)
Subject: RE: BS: Mechanic Advice Needed/Jeep
From: catspaw49

Strikes me that the cruise control is also involved even electroniaclly.......

Spaw


20 Nov 04 - 12:25 PM (#1333658)
Subject: RE: BS: Mechanic Advice Needed/Jeep
From: Sorcha

I was hoping you'd see this.....we've tried both with cruise on and off...no joy. Now what??


20 Nov 04 - 12:31 PM (#1333662)
Subject: RE: BS: Mechanic Advice Needed/Jeep
From: Amos

You could be looking at an intermittent short of some kind, possibly moisture-related or through some cable degradation if there is wiring. Loose connectors or plugs can also cause intermittent hay-wire reads on electronic units. If there's a chip involved in doing the electronic interpretation, that could be the bugger, a component-replace solution.

A


20 Nov 04 - 06:15 PM (#1333980)
Subject: RE: BS: Mechanic Advice Needed/Jeep
From: GUEST

Trade it in for a decent Toyota 4x4 or Landrover.....


20 Nov 04 - 08:12 PM (#1334085)
Subject: RE: BS: Mechanic Advice Needed/Jeep
From: Sorcha

That is fucking helpful...had one.....it died.


20 Nov 04 - 08:23 PM (#1334092)
Subject: RE: BS: Mechanic Advice Needed/Jeep
From: Bobert

Does the odometer work when the speedometer is not working?


21 Nov 04 - 04:11 AM (#1334258)
Subject: RE: BS: Mechanic Advice Needed/Jeep
From: Mark Cohen

When I had my '93 Grand Cherokee Limited, living in a macadamia nut orchard on the Big Island, the cause for most any electrical problem generally turned out to be a mouse eating the wiring.

Aloha,
Mark


21 Nov 04 - 04:53 AM (#1334272)
Subject: RE: BS: Mechanic Advice Needed/Jeep
From: John MacKenzie

I assume it's a 'fly by wire' speedo in which case it can only be electrical interferencefrom another bit of the engine management system, especially when you've replaced the sender. A big culprit for misbehaving electrics is a badly earthed engine so that's where I'd go next, if you've done that then try spraying WD40 or any water dispersant fluid on all the wiring you can find, as it may be power leakage somewhere else emitting a frequency wave that interferes with the sender for your speedo. I'm no expert on modern car electronics, and find they get more and more complicated as I get older, and less able to learn new tricks.
Giok
[check all fuses]


21 Nov 04 - 11:08 AM (#1334450)
Subject: RE: BS: Mechanic Advice Needed/Jeep
From: Sorcha

Yes, odometer works fine. Thanks, keep em coming!


22 Nov 04 - 05:42 AM (#1335095)
Subject: RE: BS: Mechanic Advice Needed/Jeep
From: Wilfried Schaum

A Jeep with electronics? Degenerate. Mine was a Korea veteran, all devices mechanic except the starter. Even the wipers could be operated by hand.


22 Nov 04 - 07:20 AM (#1335147)
Subject: RE: BS: Mechanic Advice Needed/Jeep
From: Gervase

Bloody electronics, they've got no place in a workhorse!
I had a similar problem with a Renault once, and it turned out to be a crack in the PCB behind the dash that held all the relays and clever gizmos. Engine vibration would sometimes cause the crack to open, shutting off everything that ran across where the crack was and making the dash flash and flicker like a Christmas Tree. Fixed it with some solder - but with modern cars that's probably far too crude.
(*sigh* that's why I love my leaky Land Rover!)


05 Dec 04 - 03:39 PM (#1348167)
Subject: RE: BS: Mechanic Advice Needed/Jeep
From: GUEST,Nick

I have the same problem with my 1995 Grand Cherokee and I was told that the speedometer its self is bad.


05 Dec 04 - 04:12 PM (#1348191)
Subject: RE: BS: Mechanic Advice Needed/Jeep
From: catspaw49

I think you're at the point of determining where the "brain" for the CC lies. Could be in the speed triggering device or within the ECM itself. Got a wiring diagram?

Spaw


06 Dec 04 - 01:49 PM (#1349004)
Subject: RE: BS: Mechanic Advice Needed/Jeep
From: GUEST

Asking for advice on this forum is really dumb. Go to a reliable garage and ask a mechanic to fix it Sorcha