Non-intercooled (89-91) with the wax motor KSB don't bring the heaters on prior to start (wait-to-start dash light) till around freezing. Later intercooled (91.5-93) 1st Gens preheat starting at 50 degrees. This is assuming the sensors are stock for that year and working correctly along with the rest of the system, PCM, relays, etc.

Makes me wonder about mine..

it ALWAYS preheats.. even when it was chillin in 95deg. temps

usually hear it click and have wait to start light for 2-5sec when it's warm and up to 10 so far when it's cold.

where is the temp sensor on a 93IC motor? guessing one of the 2 on the top of the intake?

Put it on a momentary switch in teh dash. Hold teh button for 5 seconds... Start the truck. Being momentary you cant leave it on by accident.

haha no thanks on the switch. when I first got my ford the glow controller was bad and my buddy said dont waste your money.. and added a switch. i proceded to burn them up in about 5sec and went out and bought the controller lol. I like the automatic stuff to work the way it should.

for that system; yes... amperage is way too high to use a plain switch, the cummins grid system uses two high amperage relays or probably better described as solenoids to control the current going to the heater. the momentary switch would just need to be wired to the control side of the relay; i actually thought of doing this with a 2 position switch and a certain value resistor. say switch up is normal operation, switch down signal runs through the resistor and fools the control module into thinking it's atleast 32* out. easy way to find this value would be with an ohm meter and a bowl of ice... let it chill to 32* and measure the resistance then find a resistor of that value... just my thoughts. but this does mean you'd have to flip the switch for normal operation after crank and start up as i assume the grid heater would continue to cycle constantly even at operation temp due to it still thinking the IAT is 32*; so momentary switch may be a slightly better idea and a little less involved

Right, the ford uses a 6v plug running of 12v to heat faster, off a solenoid as well.

I do have a degree in electronics. :U:

I'm gonna figure out which sensor i'm lookin for here and test it out.

sorry bud wasn't sayin ya didnt know anything; you told me that your kinda new to the cummins set-up and are more familiar with the fords. just makin sure there arent any grey areas is all :c:

I learn quick. haha

Alot of cummins run the grid off a momentary switch. Ford glow plugs burn out all teh time on the older trucks.

air heater
 

I have a 2002 5.9L with the air heater. It is drawing 100 amp. the post on one of the relays melted off. I think there is something wrong. Does anyone know what the amp draw should be? :humm: