Intake Grid Heater

[EOliver]

Just a quick question ... How do you check to see if your intake heater is good/bad... working? Usually I can tell when it cycles because the W. T. S. light stays on quite a while at power on, and after startup the voltmeter shows when its kicking on. It got pretty cool here in Denver today (about 38 degrees @ startup). The heater did not cycle at power on or startup. It seems my intake heater has not been working for a while now, but it has been warm enough to not warrant its use anyway.



Thanks,

Eric O.

 

[hdm48]

There is three ways.

1. do a volt drop test at the battery while it is cycling

2. do a continuinty test

3. pull it out, turn on the ignition and give it the 'lick test' [put your tongue on it]

 

[BushWakr - RIP]

Lick Test !!!!!! better be sure to have some burn ointment around I think.

In my truck the way I know its working is by some of the things you mentioned, as well as a couple of hdm48's idea's (Never tried the lick test specially if the manual says do not use ether to start if intake heaters have cycled)... but also I hear a distinct high freq. whine until the 'puter' module orders the heater relay to kick out.

Just a thought.

Regards, Bush'

 

[GeneH]

The charged air temp sensor on the intake manifold determines when the intake heaters need to come on. The intake heaters are suppose to come on when manifold air temps are below 59 degrees.

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Here is the page out of the service manual showing the location of the charged air temp sensor.

Gene

92 350 4x4

 

[ETOBICOKE]

Intake Heater

As Gene mentioned they are controled by a temperature sensor and only come on when needed.

Now if you drove the truck the night before chances are the heaters will not be required the next morning at that ambient temperature.

The grid heaters have two cycles, pre heat and post heat. The pre heat comes on at the same time as the wait to start lamp. The post heat cycles on and off after starting for about 3 minutes. For the pre heat both grid heaters are used, and for the post heat one at a time, alternatly between the two.

Now the easy way to tell if they are working is to keep an eye on the volt meter, on the pre heat cycle, the voltage will drop down between 8 and 10 volts and return to 12 volts when the heater switches off. With the engine started the voltage will drop to about 10-12 volts when the heater cycles, and go up to 14. 5 or so when off.

Hope this helps,

Neil

 

[R.E. Miller]

I had these weird problems too, replace both of your sensors on the truck, if one went, the other might be next. If your KSB sensor goes, you'll know... looks like your trying to start a 6-71 detroit at 20 degrees with no either



Wait, the computer controls this junk, try this first. Take out your battery, remove the master connector on your computer, clean the terminals, replace everything. I lost a bet with my dad with an overcharging problem on my truck because of a dirty connector.

Good Luck

 

[fastmark]

I don't know if this is your problem but I will tell you of my experience. I am from Texas and the last time I went to Co was in July of 2000. We were up at Williams Creek lake in Pogosa. The heaters would not come on in the mornings. It seamed cold enough to me. The truck was a little hard to start and would miss until it got warm. Maybe the thin air has something to do with it. It worked fine when we got back to TX, when it turned cold for the Winter.