I own a 2003 . Last week I did not plug in the truck and it would not start. I pluged it in for an hour and then it started. I put in fuel conditioner and ran it all week no problems . ALso changer both batteries since they were four years old. This morning did not plug in and no start. Do the manifold heaters go bad or relay. I felt intake manifold under air intake it does not feel warm. Also when i do start and run the volt meter used to go up and down for the heaters. Now it stays steady but i do here it click on and off.Anyone have these part changed i have 105000 mi and 4000Hrs on truck. Thanks

 

SOunds like your grid heater in manifold burnt out, what you hear clicking is your relay.

 

Probably the relay....most common failure.

 

I can't beleive it won't start without the grid heaters. Commerical and industrial engines don't have them. When it 20* or less hear I can jump in turn the key and truck starts on first or second revolution. Sounds to me like you might want to dig a little deeper into this once you fix or confirm the grid heater working.

Jed

 

I agree - I understood that the grid heaters are only required for starting in temperatures well below zero.

LongBed - do you know how to test the relay and grid element?

 

Had truck pluged in for 2 hours started firt time i cranked it. I do not know how to test the heater or relay is it simple? Should i just buy a new heater and element.would be cheaper than a visit to you know who.

 

I didn't plug mine in last night, was 0 this morning and it fired up just fine. But it did take the "Wait to Start" light a while to go out.

It went into the 3 cylinder "warm-up" idle after a short time. I went back out in 10 minutes and it was actually starting to move the temp gauge needle...just a bit. I had some heat after about 3 miles of driving.

 

Still trying to fix this . Does anyone know how to check air intake heater system? Will the heater show 12 or 24 volts on the terminals rear of heater? Do you have to check each terminal to ground. Should they read 12 volts each on cold start condition?

 

If they are working it should feel pretty warm around the grid heaters housing in the intake.

 

Connect an Ohm meter to the two lug connections on the intake and measure the resistance.
I should be less than 1 Ohm I would imagine. If it is much higher than that or in the megaohm range than your grid is burned out.
If the resistance is good than it is probably a relay issue. See if you are getting 12 volts to the grid while the "wait to start" light is on.

 

Checked voltage from relays under pass side batt both put out 12 volt cold key on . Check from each terminal on heater to ground both get 12 volts. the base does not get hot maybe a 10 F you cant feel it? I am going to order heater tommorrow. Ill let you know result.

 

Update: Replaced the heater last night. Went to start today same thing just cranks will not start. Got up 2 hours early just in case i needed to plug in 19 F outside . Wait the 2 hours truck starts right up first turn of the key. Is there a sensor to tell the engine to start cold . Temp sensor? I really want to figure this out myself. Any help which direction i should go in. P.S. The old heater was good do not feel the outside of the heater it will still feel cold at 20F The only way to feel the heat is to have the air intake off and put your hand over the grid in case you ever want to check yours.

 

Mine started all winter till just a couple weeks ago - now it has to be plugged in. I checked the grid heater and relay, nothing out of the ordinary. But still baffled as to why it suddenly changed. How much did the grid heater cost?

 

If your batteries are even questionable, the grid heaters will pull them down too far for the truck to start. I think it's called threshhold voltage. After the grid heaters cycle (wait to start goes out) then when you hit the starter there is another very high draw and you've already lost about 50% of the available battery capacity from the cold alone, there is not enough voltage for the rest of the electrical system.

I don't know how much wattage they are but it is a lot. Take a look at the wire. A lot of cars don't have any bigger battery cable than the grid heaters. The heaters themselves are really big.

My batteries were good one day and both were burried the next day.

My truck will start at -18 F by cycling the heaters twice easily even with 15-40 Rotella. It never got plugged in untill a couple weeks ago when I got a generator to lug around. Now the problem is to get the generator to start.

Most of these truck will easily start well below 0 if there are good batteries and starter. It's just better to plug in.

 

It's 38F here in DFW right now and I went out and turned my ignition on (didn't plug in truck last night). The WTS light came on for its usual 10 seconds when it's cold. I felt the intake where the grid heaters are before and after the heating period and couldn't feel any difference. There was no difference after 2 heating periods either. I agree with Longbed and don't think the hand/feel check is a valid test.

The grid heaters/ECM use the intake air temp/MAP sensor to determine when to turn on. That is the sensor on your intake manifold (behind the grid heaters). It's not the sensor on your air cleaner. However, since you are getting voltage at the heaters then this sensor and ECM must be doing their job.

See if you have any codes. Key on/off/on/off/on and leave it on. Look for codes in the odometer window.

I'm wondering if you are chasing the wrong problem because it sounds like the grid heaters are working.