Okay, here's the deal. The wait to start light doesn't light up when I first turn the key on/to the run position. Once I start the pickup it comes on for a second like it should. Is my heater grid not working? Is there something else I should be looking for? This is the motor I plan on using for my transplant so I want to make sure everything is working as it should before I pull it and add to the confusion.

 

If it's a non-intercooled truck the light should not light this time of year.

 

Even when you first turn the key on for a second???

 

nope. only if you happen to park overnight where a cold breeze blows. If the temp is above 59*F (15*C), then you won't see the light come on.

 

Yea i found this to be true also unless its collldd the light won't even come on

you can unhook the grid heater sensor and the grids should come on full time,

 

Well I'll be. I figured since all the rest of mine do it this one should to.

 

Why does it matter if it is Non Intercooled? Shouldn't the light come on when you first turn the key on, for just a second, and then go out? I know it does on my '92, and it isn't cold at all here.

By the way, judging by that picture, you have a really good looking truck. I've always liked 2wd duallys, and would have one if it wasn't pratical for me to have a W series.

 

Because non intercooled trucks have different sensors.

A non intercooled truck will light off on the first revolution if its 30* out with no grids. Its just the way they are.

And the I/C trucks have a different KSB setup so part of the WTS light is waiting for the KSB to mess with timing.

 

Because the IC trucks have this all controlled by the computer, and every key cycle the computer does a "bulb check" which turns all the message center lights on regardless if it means anything. For example if its not actually cold enough to actuate the heaters the light will still come on, but it doesn't necessarily mean the heaters are turned on.

 

I mis-read your original post and did not catch that you stated that the bulb does not light until after the truck is started. The bulb should also not come on after the truck has been started. A question is if any of the other lights come on when the key is turned on (not started). There is a bulb check on all the bulbs when the key is first turned.


So the manual I have states the process like this. This is for a 91.0 - in other words a non intercooled motor.

"This lamp is illuminated by the engine controller based on the input from the charge air temperature sensor. This light is illuminated when the ignition switch is turned to the ON position. It remains on for two seconds as a bulb test.

If the engine controller receives a signal from the charge air temperature sensor indicating that the intake air temperature is at or below 59~F (15~C), and if the engine controller has not received an engine crank signal, then the engine controller will illuminate the Wait-To-Start lamp. If this light is illuminated, it indicates that the intake air heaters have been ENERGIZED and the preheat cycle has begun. This light remains illuminated until; the preheat cycle is finished, or the engine controller receives an engine crank signal.

The Wait-To-Start lamp will flash ON and OFF if the charge air temperature sensor input to the engine controller is above maximum value or below minimum value. If either of the previous conditions occur, a fault code will be stored in the engine controller's memory."