dunno. . .might be the truck and how the computer is setup.

 

If the coolant is warm enough, the computer won't cycle the grid heater or something like that

 

Here's what I think it is. This is just my guess.


When I plug in the block heater, after about 10 mins, you can hear the antifreeze boiling if you listen closely. If you're like me and leave it plugged in for hours at a time, go out and touch the block next to where the power cord attaches. It's fairly warm.


The air intake temp sensor is on the opposite side of the engine, and almost directly across from where the heater does most of it's good.

My guess is that during the course of using the block heater, the intake manifold air is being heated through radiation, and the intake manifold physically warms up the temp sensor by conduction. I think both factors warm the air enough to "trick" the PCM into not calling for the heaters.

And I believe all the PCM does is complete the ground circuit for the heater relays that are mounted on the drivers wheel well.


I may be wrong, who knows......... I can't wait till Xmas is LONG GONE.


Peace, my compadres.

 

Gotcha jake !!

Thanks .... that makes sense. I guess that one day the heater hadn't heated it up enough. Maybe I'll add an hour to the time. Right now I have it set to warm up 2 hours before I fire it up.

 

To tell you the truth, I haven't plugged my truck in once this year. Even when the temp dipped down to 7F. Granted I kicked the idle up with a cruise control stick and let it idle for 15min in the morning.





I know, I suck[:@]

 

It was -4 below with wind chill to -30 below zero so I plugged mine it for 4 hrs and the wait to start did not come on at start up. But the grid heater sure did come on once it got a gulp of that cold outside air we had. So maybe your correct that it fools the PCM with the heat from the block as it warms up.

This reminds me I saw a remote controlled timer on sale for under $11. so I think I will go buy one [sm=bounceybounce.gif] What can I say I don't drive my truck every day so if I have it, I don't have to go out to the garage to turn on the timer as the remote is good for up to 35 ft away and it's maybe 20 ft from the house to the garage and i don't want to get cold turning it on [sm=smarty.gif]

 

Because I may have to respond to emergencies in the middle of the night, and dont have time to let the engine warm up, I leave my block heater plugged in. THis morning there was about an inch of snow on the truck, except on the center of the hood. It was 20Degrees F and the wait to start light did NOT come on. My Edge A2 In Cab Controler said the engine temp was 107Degrees. Love the heater!

 

HOLY CRAP !!

It sounds like your theory is right Demon !!

WOW .... I didn't realize that it got warm enought to melt snow on the hood though. That's wild !!

 

You talk about responding at night...lol. I had an 88 Ford Bronco II that was given to me by a family member. I had the thing running pretty good. Then one night, here come the tones.......... It's a worker, unknown occupants, etc. As soon as the engine turned over, the blues are already on, and a slammin neutral drop. Head gasket blew on the way to the station. We used it for extrication 2 weeks later......lol.

Be safe. And remember.........locomotives win on all ties...........

 

I'll put my cruise missle against your locmotive any day

Sorry, I just had to say something stupid.