Hi everybody

I have a little problem with my 00 jimmy the voltage drop down when I shift to reverse its become 9 to 10 volt and become rough running but at D or N everything is OK.

Thank you

 

Do both reverse lights work? The neutral safety and back up light switches are the same component in your auto trans.

 

yes both reverse lights work, I forget to inform that my car have dual electric fan for radiator and 2 more for ac condenser.

 

There are 4 electric fans in your 2000 gmc jimmy? I'm sorry but if it's been altered that far from factory my long distance guessing may not be worth much.

 

I still like the neutral safety/back up switch for causing the problem. It's possible that a broken one could kill your truck half to death when in reverse.

 

Start with checking into Your underhood fuse box if none of the fuses has been altered.
It hardly makes sense You're having such a voltage drop and no fuse blowns or wires burned. That drop may be normal while cranking only. So either You have such a drop, because Your battery is dead (how is Your starter cranking btw? All good?) or You have some grounding connection problem. Check with a voltmeter connected directly to a battery if You have such a drop for real.

 

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Check the motor mounts too, in reverse the motor could be shifting and pinching a wire grounding it out - been there done that

 

Thank you but motor mounts are new

Tomorrow I will check it thank you