Electrical trouble shooting

tomturkey

Well-known Member
I have a "tommy lift" tailgate on my farm/wood getting truck. This morning won't work!! The safety buzzer works when I operate the lever but no motor engagement. All operates thru a solenoid. How do I rule out either solenoid failure(safety buzzer works thru solenoid)and works, or motor failure. I did try touching the 12 volt feed cable to the motor post with no results. What else to do? My understanding of electrical systems poor. Probably just enough to ruin something. lol gobble
 
If you know the input power lead is hot (Test with a test light or volt meter). If the ground is good the the motor base, the motor may be "open" meaning internally not conducting. A tap of the side of the motor might jar the brushes into a temporary contact, but if it does work that way, expect to put new brushes in it. Jim
 
Are the solenoids where you can see them and get to them easily. If they are take a heavy wire and go form big post to big post and see if the motor spins up and the lift either tries to go up or down. If it spins up then likely to have a bad solenoid or a bad wire going to the small post on the solenoid or bad switch.
 
Old, thank you, yes the solenoid is easy access, I tried jumping across solenoid, no motor spin, tried the hammer tap still no spin. time for r&r thanks again gobble
 
Use a heavy wire right to the motor and see if it spins up. If all you get is sparks and not motor spin motor is bad and if you get no sparks at all motor is bad
 
Janicolson; Thank you for your response, yes I have hot cable to one side of solenoid and a 12 gauage hot always to one post on solenoid. When I activate the lever/switch the safety buzzer sounds but motor does nothing. Tried the hammer trick still no motor action. Thank you for your help. I think its time for R&R. gobble
 
First step to all electrical troubleshooting is to obtain a multimeter. Only then can you tell the actual voltage going in and out of the solenoid.
 
Even then you cannot always be sure. I have ran into more then one time where the meter read true voltage but when it came to load voltage it was not there.
 
I used my meter, had 12.4 vdc at feedcable. The same at the hot wire feeding the post on the solenoid. Thanks for you help gobble
 
Thanks for you input all help appreciated. Like I said, sometimes I think I know, but am not sure what I really know. gobble
 
You have power to the motor, but do you have the other half of the circuit, the ground . Make sure corrosion or rust has not isolated the motor from a return path for the 12V power.
 
(quoted from post at 22:15:46 08/04/16) You have power to the motor, but do you have the other half of the circuit, the ground . Make sure corrosion or rust has not isolated the motor from a return path for the 12V power.

I fixed a new lift gate installation 40 years ago; I had power to the solenoid but the motor wouldn't lift the gate if I stood on it.

Direct cable from the +post of the battery to the pump motor, but the ground circuit was thru the truck body. Got under the hood and found the body ground was a 10 gauge wire to the engine. No way was 300 amps going to get thru that. So I replaced the 10 gauge with a 1.0 battery cable and that fixed it.

They must have had somebody new or with a hangover make that installation. No way would an experienced guy let it go that way
 
> The first thing in auto electric [or any vehicle for that matter] is a fully charged battery.

Ah, but how can you tell without your trusty voltmeter?
 

Short it to ground and look for burnt wires in the circuit are blown fuses. That will verifi the voltage and the load was there :lol: no voltmeter needed.
 
(quoted from post at 14:07:40 08/05/16) I will assure that the ground is adequate. Thanks for your input. gobble

Unless you measure with a multimeter it's a guess. You can't see electricity like a belt or chain.
 

You wasted your time posting that he has already been told Voltmeter's lie. How can you argue with that when the first to reply with a over the top backyard shadtree reply that proved one thing he has no I.D. how to use a voltmeter his excuse they lie. :lol:

We both know in the right hands a voltmeter will 100% verify the circuit health as long as a load can be applied and that's no lie. :wink:
 

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