solenoid resistor getting hot

[mlackland]

Ok, I believe I may have found the problem. In the charging connector there is a small wire connected to something that looks kind of like a tiny lamp. I think it is actually a magnetic switch. When it is unplugged the resistor doesn't get hot, but the cart doesn't run. With the charger plugged in and everything connected the cart still runs, and the manual says it shouldn't do that. So it seems either that lamp looking switch is bad or the controller. Does it sound like I should buy a new charging connector to you? I just don't want to keep buying parts unless required.

[JohnnieB]

The lamp looking thingy is a magnetic switch (aka reed switch).
Its purpose is to disable the controller so the cart won't move while the charger is connected.
The reed switch caused so many problems (IE: failing when you were out in the middle of nowhere) that EZGO stopped putting them in their carts about 2007 or 2008. (My 2008 cart has a small fuse in that location, rather than a reed switch)

Most guys bypass the reed switch, either when it fails, or before it has the chance of stranding you someplace. See attached.

The problem you are having is the controller is passing amps when it shouldn't be. (Resistor getting hot)

Either the controller is being told to pass amps to the motor while the solenoid contacts are open, or the controller is bad.

[Cartman Z]

hi guys, jumping in on this thread as i'm at a dead end and need some advice on a similar issue:

2005 ezgo txt 36v shuttle.
cart is no-go.
solenoid no click.
resistor burning hot with cart off (even without neg terminal of batt pack connected).
old f&r switch was burning up, wires getting very hot and melting into switch.
i upgraded to heavy duty f&r which held for awhile but that eventually melted too.
batteries were way old, and not holding charge.
i installed new batteries.
my wife drove it for two miles, smelled electrical burning (which was a familiar smell from wires melting into f&r switch). she made it home, but then heard a "pop" from the battery compartment and the cart died.
i then installed all new cables, and new heavy-duty f&r switch.
fyi, i upgraded cables from 6-gauge to 4-gauge, including the runs from the f&r switch to motor, etc.
ran it around the block a few times. worked great! more torque and speed, cables cool to touch, f&r switch not melting.
backed it down driveway to park it and, without any noises/etc, it just died. no fwd or reverse.
with f&r switch in reverse, i got the beeping but only intermittently.
pushed it into the garage.
upon closer inspection, resistor between large poles on solenoid was burning hot.
troubleshooting online indicated solenoid may be bad.
i replaced solenoid, but no change. still no go, resistor still burning hot when batteries connected.
thought it could be reed switch, but that is already bypassed.
no signs of chaffing or breaks in any wiring.
pulled up floor mat (using knife and beer), opened the control box for accelerator. all wiring good, connected properly, micro-switch opening/closing as it should.
next step...gulp...speed controller?!
(alltrax 400amp ITS, series)
connect batteries, turn on key, depress accelerator, led blinks 6 times. alltrax online info states it's an undervoltage alarm.
checked batteries - holding a 38v charge.
alltrax says check voltage between B+ to B- on controller. should be within ~5v of pack voltage.
ah-ha! it reads only 12.7v.
however....alltrax says this indicates bad solenoid...which is brand new.

so i've come full circle and don't know what to do other than replace the controller - not sure if there's anything else i can test/check/etc. would love any advice you guys might have! thanks in advance!

[JohnnieB]

The pre-charge resistor is hot and the voltage at the controller's B+ is low, so excessive current is being drawn by either the filter capacitors or the MOSFETs inside the controller. Don't know which, but in either case, the controller is bad.

Replace it with an Alltrax SR48400 (or larger) controller, which is two generations newer than the AXE (or NPX) that is installed.