Hot resistor, burned pin 5, no reverse buzzer, cart won't move

[ksquared]

Hi all. I have a 2001 EZ GO TXT PDS and about a month ago I was driving uphill -two adults - and it was sluggish so I assumed the batteries needed charging. Drove normal in reverse about 1/4 mile, with buzzer, but sluggish or not at all in forward intermittently during the drive. Able to get it on the charger but it hasn't run since...even the charging was weird. Did some diagnostics and replaced solenoid. Now, the resistor is super hot to the touch even with golf cart off and in R, N, or F. Voltage drop across solenoid, B+ shows voltage of the whole battery pack and the other terminal shows voltage from only a single battery (37.4v/6.3 v). Before we realized that the resistor was getting hot we left all connected and came back to a black/sooty nut on the same terminal that only gets the single battery voltage. Checked the controller pins recently in a futile attempt to do more troubleshooting and the pin at pin 5 (red wire, which by the way is also connected to the same black/sooty nut) is black/burned. No reed switch at power receptacle, prior owner must have bypassed it. No reverse buzzer, cart does not work. I am willing to hire someone to take a look at it, but if the issue(s) are obvious I'd like to start somewhere before hiring or replacing controller only to blow it again. Note...resistor was not getting hot prior to replacing solenoid. No click at solenoid before or after replacement.

[scottyb]

Low voltage causes high amperage draw. High amperage draw causes heat which is the killer of most things electric.
It sounds like you have a burnt up controller and molex connector?
For testing see the attached diagram. You should have 36+v at each end of every red line with the key on, cart in gear, pedal down. Start testing at your B+ source.
The molex connector pins are numbered. Which pins do you have power to in the above condition?

[ksquared]

Thank you so much for your reply. I set myself up to check, and my battery pack is down to 31.3. Is it okay to charge it with this hot resistor? If so, I'll get it up to power and run the testing.

[scottyb]

Originally Posted by ksquared

Thank you so much for your reply. I set myself up to check, and my battery pack is down to 31.3. Is it okay to charge it with this hot resistor? If so, I'll get it up to power and run the testing.

Disconnect the solenoid from the pack and charge. Begin testing with no less than 36v.

[ksquared]

I have some info, although I had to note it in my own shorthand...

Battery pack measures 37.6

B+ at controller post = -31.2
B- at solenoid large post = +6.3
A1 at controller post= -31.2
A2 at solenoid large post = -31.2
A1 and A2 at motor = -31.2

Red wire measures +6.3 at Solenoid large terminal (B- is also connected to this terminal)

Pedal switch
Green and Red wires both = -31.2


Controller harness
All pins measured = -31.2 except for green and red, which both measured +6.3 at pins in controller harness

Key Switch
Yellow/white pin and White both = -31.2

Solenoid
Blue and Yellow both measure -31.2 at small posts

Reed switch is bypassed and at the bypass location red/white wires measures -31.2 at red/white pin at controller harness also measures -31.2

May also be worth noting that A1 is on large controller post, Negative battery cable is on smaller center post, and B+ is on the other smaller center post of the controller.

Also, the longer I had this hooked up, the less burning smell (new solenoid), but the resistor is still hot to the touch, although not emanating a ton of heat

Thanks for your time and help!

[ksquared]

Can anyone take a stab at what might be splitting my voltage? Does this still sound like a controller issue or is it possibly a wiring issue?

[bronsonj]

Originally Posted by ksquared

B+ at controller post = -31.2
B- at solenoid large post = +6.3
A1 at controller post= -31.2
A2 at solenoid large post = -31.2
A1 and A2 at motor = -31.2

Where are you comparing to? When you say -31.2 at controller post, where is the other lead of your voltmeter? It sounds to me like you have the positive lead on the ground from battery 5 and the negative lead on the positive of the battery pack. That would explain why all your readings are off by 6.3v of where they should be.

If the battery pack is reading 37.5 then I don't see how you are getting 31.2 everywhere unless the point you are measuring against is not the full pack ground.

Worst case scenario, can you post a picture showing what leads you are connecting the voltmeter to?

Also, golf carts are not like cars in that the frame isn't grounded so you can't reference that as your negative half of the circuit.

[ksquared]

Thanks for responding. I'm putting the black negative lead on the negative post on the last battery...the one furthest right and front if you are sitting in the front seat. I just pulled up a TXT battery configuration at another post on this site and it looks like I should have been putting the negative lead on he battery furthest to the right and back row?

[ksquared]

Should I just replace controller?

[scottyb]

are you reading 31v between the pack and the solenoid?
Replace the battery cable to the solenoid.... do you have a spare?