cfd511 Posted September 15, 2019 Share Posted September 15, 2019 So yesterday my electrical tarp cover stopped working on my 2000 Mack rd with Hrg 15 yard body. I check the switch and Solonoid and all seems to be working . I get power up to the motor . One sides hot for open and the other side hot for close when switch is pressed but motor doesn’t spin until you ground motor to bed . I think it’s a ground issue but my new dunp bed sub frame is welded and bolted to Mack frame so what could be causing this . Please help Quote Link to comment https://www.bigmacktrucks.com/topic/59026-electric-tarp-cover-fail/ Share on other sites More sharing options...
fjh Posted September 15, 2019 Share Posted September 15, 2019 (edited) Run a decent size wire from the truck frame to the box frame for ground or wait till you lift the box a bit to establish a descent ground Edited September 15, 2019 by fjh Quote Link to comment https://www.bigmacktrucks.com/topic/59026-electric-tarp-cover-fail/#findComment-432164 Share on other sites More sharing options...
tjc transport Posted September 15, 2019 Share Posted September 15, 2019 this does not sound rite. on my electric tarps, there is two wires going to the motor. there is no ground to the body. the tarp motor is a simple DC motor. to reverse direction you reverse polarity of the power wires. when in cover position, power is on one terminal and ground is on the other. when in uncover position, power and grounds are reversed. the tarp motor works the same as a power window motor does. Quote when you are up to your armpits in alligators, it is hard to remember you only came in to drain the swamp.. Link to comment https://www.bigmacktrucks.com/topic/59026-electric-tarp-cover-fail/#findComment-432167 Share on other sites More sharing options...
41chevy Posted September 15, 2019 Share Posted September 15, 2019 Is there a ground wire in the switch connector like a power window switch? Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment https://www.bigmacktrucks.com/topic/59026-electric-tarp-cover-fail/#findComment-432169 Share on other sites More sharing options...
cfd511 Posted September 15, 2019 Author Share Posted September 15, 2019 Yes the ground wit and power wit come from battery to a relay box with three wire that run to a open and close switch . I put a test light on the relay box and both sides light up on the relay incoming and outgoing . It has to be a ground issue I think because if I ground both poles to the bed and hit the switch it works quick . Quote Link to comment https://www.bigmacktrucks.com/topic/59026-electric-tarp-cover-fail/#findComment-432178 Share on other sites More sharing options...
tjc transport Posted September 15, 2019 Share Posted September 15, 2019 it is very possible the relay box is bad. is it a small electronic control box, or the large old fashioned relay box? Quote when you are up to your armpits in alligators, it is hard to remember you only came in to drain the swamp.. Link to comment https://www.bigmacktrucks.com/topic/59026-electric-tarp-cover-fail/#findComment-432180 Share on other sites More sharing options...
Ezrider Posted September 15, 2019 Share Posted September 15, 2019 (edited) both wires should rest on ground then when you activate the switch it puts power to one side or the other. you should have a good solid ground on both motor wires when the switch is off. Edited September 15, 2019 by Ezrider Quote Link to comment https://www.bigmacktrucks.com/topic/59026-electric-tarp-cover-fail/#findComment-432185 Share on other sites More sharing options...
thomastractorsvc Posted October 3, 2019 Share Posted October 3, 2019 my 2 cents. My buddys tarp motor was acting like that and one of the poles was broken free in the motor. This was found after he brought it to my shop and he already replaced the switch and wire. I disconnected the wires and hooked up to my multi meter they showed 12v ots both sides in accordance with the switch, if you grounded the motor it would work, I told him the motor was bad he didn't believe me so I took one I had and hooked it up and showed him. Took the old one apart and the terminal was broken loose in the motor. 2 Quote Robert"I reject your reality and substitute my own." Link to comment https://www.bigmacktrucks.com/topic/59026-electric-tarp-cover-fail/#findComment-433267 Share on other sites More sharing options...
cfd511 Posted October 20, 2019 Author Share Posted October 20, 2019 Thanks all for the input . I actually found a broken wire in the frame rail which fixed it . Quote Link to comment https://www.bigmacktrucks.com/topic/59026-electric-tarp-cover-fail/#findComment-434193 Share on other sites More sharing options...
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