1997 M1081A0 No crank

[Ineedatruck]

My 1997 M1081A0 will not crank. I have not tried to use jumpers or anything to bypass anything to try to get started.

The truck will now power up with the low air alarm, oil light in the dash is on, and N N on the transmission controller is there after the K2 relay was replaced. When I press the red start button, I hear the relays clicking in tne PDP.

I started troubleshooting using the manual using the No crank section.
1. Step E2.1 The starter P81 connector’s wires are already joined together.
2. Step E2.2 Continuity is present between the solenoid left terminal stud to the motor ground terminal stud.
3. Step E2.3 I do not have 24 volts on the TL26.
4. Step E2.4 I do not have 24 bolts at TL9 on the auxiliary starter solenoid. I identified TL9 based on the picture in the manual. (Out of curiosity, I checked the other side of the auxiliary solenoid on TL 24 and I did have 24 volts. I did not pull of the solenoid. I used the manual to find TL9 and TL 2. After I got done, I wondered if the solenoid had been flipped or is it normal to have 24 volts at TL24. I go to step 8
5. E2.8 I have 24 volts terminal lug TL12 so the manual says to replace either wire 14 from TL55 to TL9 or replace start charging cable assembly.

I need your help.
Is the 24 volts at TL24 at step E2.4?
I am unable to find para 2-40 and para 7-82 to instructions. If this is what I should do, can you point me to the manual?

Is there a way, I could see if this truck will start as things are now?

How you would move forward?

Thanks.

 

[Ronmar]

A single click when you push the button or multiple/pulsing clicks?

If multiple/pulsing, what is the voltage at the power panel WHILE you are pushing the button. Pulsing relays is classic low voltage caused most likley by bad connections. Remember voltage isnt good untill it is good under load.

If it is only a single click, that releases with the button release, that is probably K1, the starter relay. Thats good news as it indicates the starter control circuits are working.

Does anything go click under the cab? K1 feeds 24V down to the large aux start relay on the drivers frame near the power steering reservoir. It shoumd also go click when you push the button..

 

[Ineedatruck]

A single click when you push the button or multiple/pulsing clicks?

If multiple/pulsing, what is the voltage at the power panel WHILE you are pushing the button. Pulsing relays is classic low voltage caused most likley by bad connections. Remember voltage isnt good untill it is good under load.

If it is only a single click, that releases with the button release, that is probably K1, the starter relay. Thats good news as it indicates the starter control circuits are working.

Does anything go click under the cab? K1 feeds 24V down to the large aux start relay on the drivers frame near the power steering reservoir. It shoumd also go click when you push the button..

Ronmar,

I go back to work and will get back over there to the truck this weekend.

I hear one or two clicks in the direction of the PDP. I thought it was two. I have not heard any clicks under the cab. I will get more information, and let you know.

Thanks

 

[Ronmar]

The manual and schematics are an acquired skill, and can take some time to learn your way around. Because this is such a common issue, I drew up a simplified one page schematic of the A0 starter system. this may help you work your way thru the issue.

Good Luck.