Cat 257b, had lights on dash, turn key, now nothing.

[aheeejd]

I have a 257b, it has been sitting for about 6 months as I worked to save up for new drive motor. Replaced motor, filled hydraulic tank. Now I should have tested battery 1st,but I did not. I hooked up charger, 12v 30amp for half hour. Then I put charger to start mode, hopped in cab, pulled arm bar down. Turned key, & I had lights. Turned key to start position & nothing. Dash lights went out. I checked reset button above motor on left hand side. Nothing. Battery reads 12.8v.

Serial # is SLK06218
I'm not very handy with wires, drawings or a volt meter. I hope I didn't fry something. That drive motor was not cheap.

I checked key 10 amp fuse. And it was good. If anyone could please help that would be great.

 

[Nige]

I'm not very handy with wires, drawings or a volt meter.

Then possibly you need to find someone who is.?
All the info is available but it needs someone who can understand an electrical schematic and use a multimeter.
Start with the basics though. Pull off both ends the battery cables, clean all the terminals, etc. Reassemble and tighten. What do you have to lose.?

 

[aheeejd]

Wiil do. And I do have someone. Just a matter of getting him here. But yeah I'll do the basics & report back. I think you are the person that helped me with the LH drive info a while back, via conversation. If so thank you.

 

[aheeejd]

So I cleaned things, battery terminals. Cleaned battery cable connectors. I checked all fuses. All good now. I did have a blown one, but previous owner stuck some staples on the prongs so it appeared good. Shake my head. Arm bar is good, seat switch is good,.door switch is good. But.....no power to key switch. So could anyone suggest what to look for next. I have the schematics & I believe I said before, not to good with wires & volt meter. My friend that found no power, had to leave, & I'm waiting for him to come back. Is there anything I can look for in the meantime.. I'm much better at turning wrenches, then wires....... Ugh. Thank you

 

[Nige]

Arm bar is good, seat switch is good,.door switch is good.

Just FYI. A malfunction in any one of those switches is not going to prevent the engine from starting.

I checked all fuses.

There are 3 BIG fuses in the back wall of the cab inside the engine compartment, under the black covers. Have you checked them.?

Also there is a stud in that same area with a number of wires fastened to it. It's just to the left of the 3 red caps and circled in blue. Set your meter to DC volts and measure the voltage from that stud to the frame of the machine.

 

[Nige]

There are 3 BIG fuses in the back wall of the cab inside the engine compartment, under the black covers. Have you checked them.?

I have to correct that. Your machine is a B Series and the photo above is from a later model that has a different fuse arrangement.

See below. Two things to check; the 105-amp main circuit breaker #8 in the left side of the engine compartment (has it popped out.?) and clean the connections/ensure the hardware is tight on the ground strap #3.

 

[aheeejd]

Well well well, after cleaning out some leaves to reveal the ground strap #3. It is severed. Looks like it has been severed for long time. How this happened is beyond me. Probably 5 or 6 years ago my father in law had brand new engine put in after he tipped it forward with raised bucket, and was in poor health, bad heart. Anyways, I will make a #4 awg ground cable & report back. Breaker #8 was fine. Not popped. Thank you very much Nige for your help.
I almost want to clamp strap together with needle nose vise grips just to see if I get dash lights....

 

[aheeejd]

Ok I replaced ground. No change, no dash lights. I checked & cleanedl the terminals & nothing. The electrical guy is on his way to see if he can figure out why key has no power so we'll see what happens there

 

[aheeejd]

I fear this is gonna take a while. Electrical guy came. 12v at battery, 12v at fuse box. 8v at key switch, & then 0v when key turn. Disconnect wire from switch, still 8v on the wire. But, he had to go. He took schematics & manual with him (big service manual).

Anyways, any of this mean anything to anyone? All wires that can be seen look good. No pulled, frayed etc.

 

[stefuel]

I'm not a Cat guy and I don't play one on TV. To me it sound like a power or ground problem. You say you cleaned the battery terminals. Check the other end of the NEG battery cable where it attaches to the engine and make sure it's clean and tight. Then check the positive battery cable back to the starter and make sure they are tight. Measure for 12V at the starter. Can you follow that wire with 8V back to it's source? Not sure how Cat does it's wiring harnesses but you could have a burned connector where two harnesses come together. Anyway, certainly sounds like a bad connection issue.

 

[Tall.Timber]

I fear this is gonna take a while. Electrical guy came. 12v at battery, 12v at fuse box. 8v at key switch, & then 0v when key turn. Disconnect wire from switch, still 8v on the wire. But, he had to go. He took schematics & manual with him (big service manual).

Anyways, any of this mean anything to anyone? All wires that can be seen look good. No pulled, frayed etc.

Sounds like a text book bad connection somewhere on that 12V wire to the key. TINY connection is made at the bad point which allows just enough electrons to show 8V on a meter. but when you try to use that power it reads 0V. Start following that wire backwards and check voltage at any points possible. Once you find that point that reads 12V I would just install a jumper. A short/open detector tool may be useful for help tracing this wire.

 

[Nige]

I fear this is gonna take a while. Electrical guy came. 12v at battery, 12v at fuse box. 8v at key switch, & then 0v when key turn. Disconnect wire from switch, still 8v on the wire. But, he had to go. He took schematics & manual with him (big service manual).

Anyways, any of this mean anything to anyone? All wires that can be seen look good. No pulled, frayed etc.

I think the only logical way to approach this is for the electrical guy to use the schematic and start testing for power right from the point the 12v leaves the battery and moving in the direction of the key switch one component/connection at a time.

The first stop is the starter motor, after that it is the 105-amp breaker that you checked before and found was not popped - but this time you are looking for battery power on both the incoming and outging connections on said breaker. TBH I would suggest to disassemble & clean the blue-arrowed connections at both the starter (1 connection with 2 cables) and on the 105A breaker (2 connections, incoming with 1 cable, outgoing with 3).