Cat 424D backhoe loader no forward or reverse

[katlegok083]

Good day

I have a caterpillar 424D backhoe with serial number RXA

Machine has lost the ability to move forward nor reverse

Checked for power on the solenoids located ontop of transmission
They have no power.
Also checked the wiring harness to the solenoids no power
Looks like there is no power to both solenoids


All fuses good
Both solenoids tested on another machine,& they seem to work fine
The white wire ( ) seems to be having power checked on the fuse box and also


Any assistance will be highly appreciated

 

[Nige]

I sent you an electrical schematic. Check your message inbox.

 

[ador]

Sir, wheel Loader Liugong clg 856 model 2013.only working forward/reverse.2nd,third and fourth gear not working.what are possible causes?

 

[Nige]

Sir, wheel Loader Liugong clg 856 model 2013.only working forward/reverse.2nd,third and fourth gear not working.what are possible causes?

No idea, sorry. Don't work on the brand of machine.

 

[katlegok083]

I sent you an electrical schematic. Check your message inbox.

Thanks, received and went through the schematic.( not soo easy to understand)
discoveries
no power to forward or reverse solenoids

diagnostics: -
tested forward and reverse handle on known good backhoe & it works fine
tested both solenoids on known good machine & they work fine

When testing FNR plug wires, the white wire has power, all other wires no power
when trying solenoids manual by pushing with a pin either to reverse or forward position the transmission responds therefore my issue is electronics related not the transmission

could it be the neutral safety switch or key switch relay (cant find their location)

 

[TVA]

For a moment I’ve got exited, and thought “someone got 424 in the USA?! . Then I looked at OP’s country.

 

[TVA]

Thanks, received and went through the schematic.( not soo easy to understand)
discoveries
no power to forward or reverse solenoids

diagnostics: -
tested forward and reverse handle on known good backhoe & it works fine
tested both solenoids on known good machine & they work fine

When testing FNR plug wires, the white wire has power, all other wires no power
when trying solenoids manual by pushing with a pin either to reverse or forward position the transmission responds therefore my issue is electronics related not the transmission

could it be the neutral safety switch or key switch relay (cant find their location)

Neutral safety only job is not to let your starter work when you are not in neutral.
There’s should be two wires in the FNR switch that do that.
If you have power feed to FNR - get the multimeter in to “buzzer mode” and start testing whether the FNR switch is switching OK. Put one lead on that supply contract, start switching the switch and test the connection

 

[TVA]

Another thing: are you sure your machine is getting off of the parking brake?

 

[TVA]

OK I’ve missed something there. Not sure about this particular machine, but most of the times there should be two wires under power: one is for neutral safety switch, the other is for FNR.

Looks like you are missing one. Or I’m wrong

 

[katlegok083]

thing: are you sure your machine is getting off of the parking brake?

thanks for the reply,
the electric parking brake? the switch has power when testing with a multimeter
toight i got hold of a 3 way toggle switch (ON / OFF / ON ) that i gave direct power from the battery and connected it to the FNR solenoids, machine does move forward & reverse

so it seems i lost power to the solenoids wiring or to the FNR handle plug because the handle works fine on another machine

 

[katlegok083]

OK I’ve missed something there. Not sure about this particular machine, but most of the times there should be two wires under power: one is for neutral safety switch, the other is for FNR.

Looks like you are missing one. Or I’m wrong

any idea where the neutral safety switch is located on this particular machine?

 

[Nige]

any idea where the neutral safety switch is located on this particular machine?

The location of every component is shown on the electrical schematic that you already have.

 

[Simon C]

I could find the component on the schematic, but I think that lots of people find it harder to find the location off of a PDF. It took me some time to learn how to follow the wires. Plug in locations, and relay and solenoid locations are easy to find if you know how. Maybe the member is having a hard time to find it.
Simon C

 

[katlegok083]

I could find the component on the schematic, but I think that lots of people find it harder to find the location off of a PDF. It took me some time to learn how to follow the wires. Plug in locations, and relay and solenoid locations are easy to find if you know how. Maybe the member is having a hard time to find it.
Simon C

True
It's really hard to follow those wires

 

[Vetech63]

True
It's really hard to follow those wires

I have Cat prints blown up to 24" x 36" all the time.

 

[Nige]

any idea where the neutral safety switch is located on this particular machine?

Do you mean the transmission neutralizer switch.?
Is it not #5 on the top of the transmission control lever.? See attached.

 

[katlegok083]

Do you mean the transmission neutralizer switch.?
Is it not #5 on the top of the transmission control lever.? See attached.

thanks for the reply
the switch on the gear lever im aware of, when testing power to it,there is no sign of power, tried the neutralizer switch on the front bucket lever there is also no power to it..

seems that the only active neutralizer that has power is the 1 on the FNR lever

 

[Nige]

the switch on the gear lever im aware of,

If that's the case I'm baffled as to why you were asking where the neutralizer switch was.?

The function of both neutralizer switch circuits is not to carry voltage/current but to provide a path to ground so that the Shuttle Control will recognize if the two switches are open or closed.
Whichever of the two switches is operated the logic is the same as far as the Shuttle Control is concerned. "Do I see ground on Pin 9 (one or other switch is pressed) or do I not see ground on Pin 9 (neither switch is pressed).? If I see ground do A, if not, do B."

A resistance/continuity test on this circuit might potentially give false results.
Use a decent wattage test light connected to batt+ and apply it to Pin 9 on the Shuttle Control. Press each of the neutralizer buttons in turn then release. Does the test light come on each time.?

 

[katlegok083]

Thanks for the reply guys..
Got an electrician come out to check wiring.. some of the wires where cut by rats he had to cut and rejoin some wiring machine now has forward and reverse

 

[Vetech63]

Aren't they soon cute!