Engine/Transmission (1994 - 1998) Elect. problem?

[HCannon]

I got a 98 that has lost all the gages and the alt. has stopped charging. Everything else works as it should including all the warning lights that come on when you turn on the key. The mileage indicator dose flash off and on and the gages will move a little when you first turn the switch on. I am thinking there is something common between the two or do I have two problems? Any kind of help would be nice. I thank it will be a loose ground wire some where but where?

 

[DieselDoghouse]

One of the most common problems is "losing" the crankshaft sensor—it feeds info to generate the tachometer signal but also informs the CPM of engine running status—without which the CPM will not enable alternator charging and may disable varied gauge functions. Grab a scan tool and see if you have on of several codes for malfunction of the cranky sensor.

 

[HCannon]

DieselDoghouse, where is the crankshaft sensor located? I dont have a scan tool but do have another pickup just like this one. Could the sensors be traded, that should tell? I just had a rebuilt transmission installed so something could have happen then. It has a nv 4500 standard. This is a 12 valve so loss of the sensor wouldnt bother running of the motor? Thanks, Harvey

 

[Missouri Mule]

The Engine Speed Sensor (crankshaft sensor) is located on front engine above and to left of vibration damper (aprox . 5 in. ).

If the engine speed sensor/broken wire is at faullt the Tach,A/C ,Charging(voltmeter) and sometimes the Speeddometer will not work.

I agree the problem could be a ground or loose connection (check the instrument panel connector).

 

[HCannon]

Thank the both of you for your imput to my problem. I disconnected the crankshaft sensor on the other pickup and the tac. and amp. were the only gages that died. On this one, all the gages, including the spedo. are down. Would you know where the gages get their ground? There has to be something common between the alt. and the gages. If the Alt. was bad it shouldnt affect the gages, or could it? I keep a rebuilt alt. that I could change this one out with. I did pull the instrument panel and everything looked. I sprayed everything down with a contact cleaner before putting back together. I am 70 miles from anyone that I would trust to look at it. Thanks again, Harvey

 

[Missouri Mule]

In the service manual it states that Ground 201 and 202 are in the same place but in the diagrams they are in two different locations.



G201= lower right of instrument panel(FRONT SIDE)

G202= is grounded behind or below radio

They are very close to each other

 

[fest3er]

IIRC, if you hold the trip reset button in, turn the key on, and wait for the trip display to display 'other than normal', the cluster will go through a self-test, including setting the gauges to 0, 25%, 50% and 100%, then back to 0. If this works, you know the cluster is OK.

Then check for codes. Most likely, there is a problem with the CCD bus (two-wire bus 'network' Chrysler uses to communicate among modules like the CAB, PCM and a couple other things.

 

[HCannon]

Well, it turned out to be simple. A fuse that looked good that wasnt. I went back and checked them with a meter and there it was! Dont guess it was all bad, I learned a lot about how it all works. I have a set on manuals ordered so maybe I will be a little better prepared next time. Thanks everyone. Harvey

 

[DieselDoghouse]

If Billy Shakespeare was a mechanic he would still say "All's well that ends well"!

 

[thermalking]

Great Catch! Needed CPS, not PCM

The great info here saved me $500 or more.

My mechanic said my 98 Ram needed a new Powertrain Control Moldule (PCM) because all gauges were dead, odometer was flashing, and even a new alternator wouldn't charge. Hoping for a cheaper solution, I studied this and similar forums which suggested unplugging the Crank Position Sensor (CPS). I did so, and Presto! -- everything worked except tachometer and alternator. That proved my PCM was OK and it was probably just a bad CPS. So, I ordered a new CPS for $100 and now everything works fine.