Please help!!

[Harleysiber]

Ok here's the deal. I just bought an older electric golf cart for my camp. when I got it home I through some new batteries in it and it wouldn't work. Here is what I did. I took the batteries out of my uncles running cart and when I got nothing I checked all the battery connections they were clean and tight. So I took a piece of hevy gage wire and jumped the solenoid (connecting both sides of the big terminals) by doing this I was able to get it running. I checked the to make sure it would go both forward and reverse while jumping the solenoid and it did. also while jumping the solenoid I gave it throttle and you could hear the motor increase in speed. So I took the solenoid out of my uncles running cart and put it in mine and I got nothing. I also hot wired the ignition thinking it was a bad switch. It seems the only way I can get the motor to run is by jumping the solenoid. My cart is either a 1975-76 ez-go 36v electric cart I'm begging you please help I'm at a loss.

[scottyb]

Stop begging it's unbecoming

1st = understand how the solenoid works.
2nd = make it work


A quick overview of the solenoid is :
The solenoid is a HD on/off switch or Contactor
the connection is made /broken between the 2 large terminals. The 2 small terminals are the activation circuit. typically one terminal will have a constant negative connection to the pack. When Positive power is applied to the second small terminal the contact is drawn up against the spring to make contact. When power from either side of the activation circuit is removed then contact is released and the spring pushes it away interrupting the circuit ...It doesn't matter which small terminal is neg or pos on the activation circuit so long as you have one of each....

[JohnnieB]

Welcome to BGW.

If you your cart has an electronic speed controller, the solenoid activation circuit ought to be something like this.
Red line is from Battery + to solenoid coil and Green line is from Battery -.

If it is a Resistor Cart, the circuit will be a little different, but the current path to the solenoid coil from B+ to B- will still go through a series of switch contact.

[Canine_Rescue_Pilot]

Hi Harley, Welcome.
I'm with ScottyB on this... Deep Breath. We've all been there... the fine line between frustration and despair.

Remember what a solenoid is... a giant remote-controlled contractor switch.
Sounds like you've already got part of your problem solved. You know that if you jump the solenoid, your motor works.

Grab a voltmeter. Check the low voltage (coil side) of your solenoid.
Does it get voltage when you press the accelerator with the cart on, key on, etc.?
Does that voltage change from zero to high when you press on and off the accelerator?

If the answer to both of those is no, the follow the wires back. You will likely find one goes to a micro switch, often connected to and part of the mechanical F-R switch. Is that switch working properly?

That micro switch is used as a sort of "Neutral" - it prevents the solenoid from activating the motor if the F-R switch is not properly set in F or R. It is also inline with your key switch.

You said your cart is a 1975 or 1976? Vintage!