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Following your directions, K11 pin 30 measures 22.6v without a load. Pushing the start button has no effect, does not change the reading.

It started out as something else. After replacing the LBCD the “clicking” issue went away. I also discovered the TCU was bad and changed that. Now everything powers up as normal but no response from the start button. I mentioned the generator in case that might be a factor.

Transmission controller light up as it should. Circuit breaker also tests fine. FYI, I can start the truck by jumping the auxiliary relay on the frame, but not with the start button. I’m watching the generator now. It flashed alternating amber for several minutes, now is alternating with green...

K11 on this PDP is the ALT EXCITE relay. Pin 30 shows 24v but for some reason it will not supply power to 87. I jumped pin 30 to 87 and 87a and still no power to Alt Excite.

I have power to the TCU, and power to K26, but nothing at K11. Where do I go from here?

I swapped the PDP with a known good unit and still no start. I did notice K11 does not light up with the ignition on.

Now the spare TCM failed. Something terrible is happening.

I recall a reading a post a while back that referenced the lights on the generator, one led above 14v and the other above 28v. With the engine running, both lights are flashing amber, alternating between the two. Please remind me what that signifies.

Finally had a moment to work on this girl. I swapped out the LBCD with a borrowed unit and that cured the incessant clicking. Now I have full and steady power to the cab, but the start button had no effect. I raised the cab and jumped the solenoid on the frame and it fired right up. Then I...

It has to something like that. I’ve ruled out practically everything else to no effect: -bypassed battery disconnect relay -swapped TCM with a known good unit -recharged the batteries individually -bypassed the LBCD -added extra ground My next idea is to cannibalize the battery disconnect and...

Jumped the ignition to battery bolts. No change, still cycles on and off. I’m pretty confident that both the 12 and 24 volt ignition relays are clicking. Everything powers up, dahs lights and low air alarm for 3 seconds. Them the 12v clicks followed immediately by the 24v relay, then all goes dark.

Here are some photos of the ignition relays under the PDP. You’ll notice a set of two wires coming from both with the handwriting label that says BAT RELAY.

The new battery disconnect is clicking. Either one or both of the ignition relays are also clicking. I can hear it clear as day. It also feels like they’re both clicking, but it also might be the vibration from one clicking that makes the other feel the same. The ignition relays in my truck have...

No. I apologize for being unclear. Underneath the power distribution panel are the two large relays, a 12 and 24v. Each have a set of thick gauge cables that (I think) link the battery and ignition together. They also have a set of two small wires that connect to the disconnect relays. When I...

During one of the “dead” moments when all switched were powered on and nothing was happening, I jumped the 24v relay underneath the control board and found that would “awaken” the truck, but only to continue its cycling on and off. I jumped both the 12 and 24 relay and no change.

I checked that LBCD box (I assume that is also referred to as a polarity box). Both 24v and 12v read fine. Still I removed each cable and cleaned them off and retightened and the result was the same. I also checked the battery and ignition bolts in the fuse panel and they came back fine. while...

The original relays finally quit so I replaced with the newer model, single box relax setup. We turn battery and master switch to on and dash powers up as usual. Push the start button and one of two things happen: 1. Everything goes dark, like a blown fuse. Cycle the battery disconnect switch...