Wait to start light bulb out or more serious issue?

[Foxclub83]

Wait light isn’t coming on. The screws are seized. Is there an easy way to test to see if the bulb is bad or if there is a more serious issue? The truck is still starting and running fine.


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[98G]

What's ambient temp where you are?

 

[Mogman]

Pull one of the wires going to a glow plug and put a volt meter on it, when the run switch is first switched on (engine cold) there should be 24V there for oh 8 seconds or so, then depending on what EESS box you have it will ether start to pulse the 24V or the voltage will be reduced significantly for another minute or so.
If that looks good then you probably have a bad lamp.
The screws for the lamp go into plastic so I am surprised you say they are rusted (frozen)

 

[Milcommoguy]

WAIT to START lamp ??? is a LED. To test locate the two leads to the WAIT fixture. Can be a PITB being short wires. Wire tagged 571 to ground with truck in run RUN should illuminate WAIT LED. This assumes wire #27 has 24 volts on the other WAIT wire. Another assumption... LED could be toasted, could happen.

Could be a "not so smart" controller box. We know those are troublesome.

WAIT can lead to Stop, CAMO

 

[TOBASH]

Read my posted schematics regarding under the hood PCB/EESS plug. Then test if the glow plug hot wire (attached to pin-D) gets current and voltage when the vehicle is turned on. In essence follow Mogman’s instructions while using the schematics I posted.

The thread containing the schematics is posted in my signature line.

 

[mrfarb]

I agree, you can test for it. I had a similar situation with a 1097a2, replaced the wait light assy and it functioned as intended after that so they do go bad. The service TM gives instructions on replacing it which includes removing the dash panel, I was able to loosen the left side and wiggle it out without completely disassembling the dash panel.

 

[TOBASH]

I agree, you can test for it. I had a similar situation with a 1097a2, replaced the wait light assy and it functioned as intended after that so they do go bad. The service TM gives instructions on replacing it which includes removing the dash panel, I was able to loosen the left side and wiggle it out without completely disassembling the dash panel.

What I did was probably sacrilege. I removed the starter switch. I ground down the back of the LED for the glow plug light. I then was able to wiggle the thing into place and use screws to secure it.

Not exactly what is in the technical manual and yet it worked great for me. The key was grinding down the back of the LED without damaging the LED. That light is way too bulky to pass as-is.

I recognize that my method is not what is recommended in the technical manual.

 

[Foxclub83]

I have 24v at the #27 wire. I noticed today the wait lamp flickered for a split second when the switch turned to run. I’ll have to get someone to help me with checking volts on a glow plug wire when the switch turned on. I’m thinking the start box is bad.


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[98G]

I have 24v at the #27 wire. I noticed today the wait lamp flickered for a split second when the switch turned to run. I’ll have to get someone to help me with checking volts on a glow plug wire when the switch turned on. I’m thinking the start box is bad.


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I've had them do that when the batteries start to go bad.