help with 2003 ezgo electrical issues. new batteries new controller, not moving

[CustomGolfCartGuy]

i have a 2003 ezgo txt here in the shop, and teh customer put new batteries in it and shortly after the controller went out. no reverse buzzer, no clicking of the solenoid. so i put a rebuild fsip controller in it and it ran a bit on the lift so i was going to get it down and take it for a test drive the next day. well the next day i go to take it for a spin and it wont go. i could here the solenoid clicking so i put a new solenoid on it and now i have nothing. still have the reverse buzzer but no clicking of anything. help i, lost on this one. thanks

[mjroman20]

Controller model number and battery voltage? If the issue started with a battery change I would suspect the wrong voltage or some error in connection.

[CustomGolfCartGuy]

Originally Posted by mjroman20

Controller model number and battery voltage? If the issue started with a battery change I would suspect the wrong voltage or some error in connection.

batterys all look good. 6.3 each pack voltage of 38. we didnt do the battery switch here, but everything looks ok.

the controller is curtis pmc 73326g05.

[CustomGolfCartGuy]

Anybody?

[JohnnieB]

That is a part number for a Curtis 1206MX controller, so you are working on a PDS cart that is 14 years old and there are a lot of things that will keep a PDS controller from working, so it might not have had a bad controller when it came into the shop.

Attached is a schematic with all the wires and cables that have to have pack voltage (38.2V) on them to get the cart to move forward. Each of the 15 wires/cables highlighted has a connector at each end that could be corroded, plus the is a "sonic" weld on the wire going to J1 Pin-5 and a reed switch feeding the wire going to J1 Pin-4. In addition to the reed switch, there are 5 other sets of switch contacts that could have failed.

Since the controller appears to be dead, the starting point would be J1 Pins 4 & 5. They should have pack voltage on them 100% of the time.

[CustomGolfCartGuy]

Originally Posted by JohnnieB

That is a part number for a Curtis 1206MX controller, so you are working on a PDS cart that is 14 years old and there are a lot of things that will keep a PDS controller from working, so it might not have had a bad controller when it came into the shop.

Attached is a schematic with all the wires and cables that have to have pack voltage (38.2V) on them to get the cart to move forward. Each of the 15 wires/cables highlighted has a connector at each end that could be corroded, plus the is a "sonic" weld on the wire going to J1 Pin-5 and a reed switch feeding the wire going to J1 Pin-4. In addition to the reed switch, there are 5 other sets of switch contacts that could have failed.

Since the controller appears to be dead, the starting point would be J1 Pins 4 & 5. They should have pack voltage on them 100% of the time.

i checked all the wires for corrision before ordering the controller, but i will double check everything you have listed and see what i come up with and i will let you know. thanks alot

[JohnnieB]

Pins 4 & 5 are what powers up the controller's electronics. (after going through the Run/Tow switch - which powers down the controller in Tow) Pin-4 feeds the logic circuits and Pin-5 feeds the external switches.

A quick and dirty way to check if the controller is powered up is to push the cart while the Run/Tow is in Run. If the beeper starts beeping rapidly and regen braking kicks in, the controller is powered up.

[CustomGolfCartGuy]

new weird piece to the puzzle. i was checking things over on the cart and i checked the pack voltage and it was 38, then when i hit the pedal it goes to 18, then to 20, 25, 36, 38. jumping voltages every second that the pedal is down. it doesnt jump down at all only up. what the hell causes this?

[mjroman20]

Its normal for the voltage to drop when you first pedal down as the current draw to start the vehicle moving from rest is higher than maintaining drive current. The voltage then rises back up as the current draw subsides to a lower value.

However below 30ish volts seems insanely low to me.

[JohnnieB]

Originally Posted by CustomGolfCartGuy

new weird piece to the puzzle. i was checking things over on the cart and i checked the pack voltage and it was 38, then when i hit the pedal it goes to 18, then to 20, 25, 36, 38. jumping voltages every second that the pedal is down. it doesnt jump down at all only up. what the hell causes this?

When you say "checked the pack voltage", do you mean you measured between the main positive and main negative terminals of the battery pack?

If so, going from, 38V down to 18V could mean one of three things.
1. Bad battery or batteries.
2. Bad high current cables and/or connectors withing the battery pack.
3. Huge momentary amp draw.

Or some combination of the three.