Archived Electrical problems 97 12v help

[Lift Tech]

When key switch is turned to the start position I am missing the following dash indicators: check engine light, gen light wait to start light,water in fuel light trans temp light. Once the truck is started there is no tach or speedometer the O/D will not engage the charging system is not working and the trans appears to be in limp mode. I have checked all fuses, relays, and wiring connectors also tested batteies and connections everything is VOM/OHM testing ok. Called dealer and they seem to know less than me. I have no way to access codes. Is there a relay or something else I am missing

 

[warlock36]

I had this happen to mine when the engine was pressure washed by the dealer I bought it from. Had to unplug the sensors and leave them to dry out. Everything is fine now. Dont know what caused the problem though. Good luck.

 

[Lift Tech]

I dont belive this is my problem, engine compartment has been dry. Thanks anyhow. any one else have an idea I cant drive this thing its cutting into spring snowmobiling.

 

[Deezul1]

Dont know what it is but I would start with the ignition switch first. What is not working when you first rotate the switch to the "Run" position before hitting "Start" . Sure sounds like either bad or dirty contacts in the switch.

 

[Lift Tech]

First thing I tried was a new ignition switch no change also checked switch harness. I am wondering if the crank shaft sensor would disrupt all of these systems through the PCM. Would be inerested in any tests for the crank sensor. Just orderedthe manual should have bought it before it was needed.

 

[kaffine krazed]

First off check all power a grounds at the PCM including key on power.



If you have power and grounds check the 5 volt refrence if it is much lower than 5 volt start unplugging sensors 1 at a time checking the voltage after unplugging a sensor to see if you have your 5 volt reference. If you unplug a sensor and it returns to 5 volts start plugging all the other sensors back in while monitoring the voltage to make sure there isn't more than 1 sensor causing the problem. Replace the sensor that causes you to loose the 5 volt refrence. Don't froget the cruise control buttons on the steering wheel are sensors unplug the clockspring connector on the steering column side.

 

[Lift Tech]

I dont have a wiring schematic yet, could you tell me which pin connectors on the PCM are positve and negative and the values they should be. Where is that 5 volt referance taken at.

 

[Missouri Mule]

Lift Tech,



As I recall anything not needed in actual starting of the enigine except a few guages, (idiot lights not included you can hear the enigne start ) are not turned on while key is in the "start" positon.



When the key is returned to "run" position all guages, idiot lights... should function.





Second problem, this seems to be the infamous " Engine speed sensor connector" or one of its wires or the sensor. ( engine speed sensor on gas engines and the overvalved ones are known as crank speed sensors. Crank speed sensors are located inside of block and reads an internal engine part that rotates).



On the undervalved ones (12v) the engine speed sensor is located above the vibration damper, follow the wires upward to the connector its hiding behind large wiring harness.



This connector tends to get dirty inside but check for loose/bent pins also (and broken wires) (loose grounds, the one by the heater grid).

 

[Lift Tech]

Found the problem and solved. The PCM was not sending a good 5 volt senor signal. The fix was to install a new PCM only 482. 00. The original part # had been updated twice, the new PCM does not require flashing just plug and go. I am very impressed with the increase in power, old PCM must have been weak in the transmission control system. Charging system seems to be much better also. Thanks for your responses.