Another lmtv that won’t start

[ghog50cal]

So I have another lmtv that will not start I can jump a wire over the post on the sylonid on the frame under the driver’s seat and it stats and fires off I have taken the dash apart and tried too ohm out the switch but I don’t seam too have power at the red button have followed the harness the best I can I don’t see any breaks in the wire all my fuses seam too be re set not sure what I’m missing

any help would be be great

 

[ghog50cal]

Everything works as it should once I just the truck from under the cab on the cylonid

 

[TomTime]

…what?
What did you do?

 

[Ronmar]

If I understand you correctly it runs OK when you jump the aux relay or start solenoid to crank it?

What relays in the power panel go click when you turn on the ignition switch. Should be K11 and K24.

Do you get an oil pressure idiot light?

what year and model truck?

 

[ghog50cal]

…what?
What do did you do?

The truck runs and drives fine if I jump the starter cylonid on the frame under the cab drivers side but I can not get the truck too start from inside the cab

 

[ghog50cal]

The truck runs and drives fine if I jump the starter cylonid on the frame under the cab drivers side but I can not get the truck too start from inside the cab

The truck is a 95ish and no idiot light on the oil on dash when I flip the master power I can hear and feel the 24v ignition and the cranking lock out click start inhibit makes something under the truck click

 

[ghog50cal]

K11 and

If I understand you correctly it runs OK when you jump the aux relay or start solenoid to crank it?

What relays in the power panel go click when you turn on the ignition switch. Should be K11 and K24.

Do you get an oil pressure idiot light?

what year and model truck?

K11 and k12 don’t seam too do anything

 

[ghog50cal]

K11 is marked excitation and k 12 is marked work lights

 

[Ronmar]

K11 and

IK11 and k12 don’t seam too do anything

I said K24, not K12…. You have a bad oil pressure sw or circuit. it controls the light and K11 and K24. K24 must energize to complete the starter circuit to energize K1 when the button is pressed. K1 in turn energizes the aux relay on the frame which energizes the start solenoid.

no oil light, no crank…

 

[ghog50cal]

O I do have an oil light when it’s not running I was thinking while it was running

 

[ghog50cal]

I said K24, not K12…. You have a bad oil pressure sw or circuit. it controls the light and K11 and K24. K24 must energize to complete the starter circuit to energize K1 when the button is pressed. K1 in turn energizes the aux relay on the frame which energizes the start solenoid.

no oil light, no crank…

i have the oil light when it’s not running I thought you meant when it was running

 

[coachgeo]

try moving your finger around to different spots on the start button..... or pull it out and jump it (hot wire it) as a test.

aka..... a few have reported the start button itself not making good contact.... thus not working intermittently... this type thing happens to rear its ugly head when it gets cold outside too.

 

[Ronmar]

Ok if K24 energizes with the oil light when you turn on the switch, does K1 in the power panel energize when you press the start button?

If I recall K1 gets power from the neutral start relay in the VIM. The start button provides the path to ground to energize K1 thru the energized contacts of K24…

 

[ghog50cal]

try moving your finger around to different spots on the start button..... or pull it out and jump it (hot wire it) as a test.

aka..... a few have reported the start button itself not making good contact.... thus not working intermittently... this type thing happens to rear its ugly head when it gets cold outside too.

It’s 72degs inside my shop lol and I tried jumping the switch all read was the first thing I did when I do that or press the switch nothing happens at all no noise no clicks nothing

 

[ghog50cal]

Ok if K24 energizes with the oil light when you turn on the switch, does K1 in the power panel energize when you press the start button?

If I recall K1 gets power from the neutral start relay in the VIM. The start button provides the path to ground to energize K1 thru the energized contacts of K24…

Do you guys think I need too pull the fuse panel out and check the back of it too check the connections I am completely out of ides and about too take a bath with a toaster lol

thanks for all your help

 

[Ronmar]

Well did you check what I asked? Is K1 in the panel going click when you push the button?

based on what is happening with K1 I can point you to some checks when I get home this evening…

 

[ghog50cal]

Well did you check what I asked? Is K1 in the panel going click when you push the button?

based on what is happening with K1 I can point you to some checks when I get home this evening…

K1 it’s not clicking or doing anything when the button is pushed or when the button is jumped also

 

[Ronmar]

Ok it will be 2 hours before I can steer you to the next check. You have a volt/ohm meter right?

 

[ghog50cal]

Ok it will be 2 hours before I can steer you to the next check. You have a volt/ohm meter right?

I have 2 snap on volt meaters and a power probe with computer hook up

 

[Ronmar]

Ok, grab a volt meter, in the power panel remove relay K1 and with the main switch on, measure from K1’s pin 86 socket on the panel to the ground test point. You should see 24V. That 24V originates at CB21, passes thru the neutral start relay in the vehicle I/F box under the passenger dash behind the kick panel and flows to K1-86. If you don’t have that, is the trans controller powered up and in neutral?

If you have the 24V at K1-86, set the meter for resistance and measure from the K1-85 socket on the panel to ground, with the main switch on, should be able to see the resistance to ground go from high to low when you push the start button. That path goes from K1-85 to K24-30. It passes thru the closed when energized contacts of K24(Pin 30-85) and from there to the start button. The second pin of the start button passes back to TB2 which is the power panel ground bus…