Engine/Transmission (1994 - 1998) Fuel Heater is Toast

[SMorneau]

I just got my truck back from the dealer for a recall and the tech, who I like, left me a note said to check my fuel heater. Well the connector to the wiring harness is totally fried (Not the one at the heater element the other end of that heater harness) . I clipped everything off and taped up the wires so they could not short or wind up in the steering shaft.



Ok, then I look at the manual and as far as I can tell this circuit is not fused. Thats seems pretty unusual and perhaps dangerous, at least to the other wires in the harness.



Of course the next step is to search the forums. I gleaned some useful part numbers and tips from this but no mention of a fuse.

According to a couple of posts, the heater turns on at 40 deg F. I live in Minnesota and i can't see any reason why this heater would need to be on at 40deg F. Hell, mine has probably been out for years.



So give me your thoughts on this:



1) I will replace the heater and harness using the screw type butt connectors (like Genos sells) sealed in shrink wrap to connect it to the engine harness.

2) I will find the origin of the high current circuit to the relay, I believe it is one of the mysterious wires at the left battery +, and install a 30A fuse in it.

3) Since I see no point in running a heater at 40deg F, I will either install a manual switch rated at 50 amps inline to the high power side of the relay, or install a 10deg F switch on the low power side of the relay. 10 deg should keep #2 flowing .

4) I will take my sweet time doing it because it summer and this has no impact on the AC

 

[illflem]

Even thought the heater is set to come on at 40° it doesn't stay on long. Return fuel to the tank will heat all the fuel to well above 40° in just half an hour of driving even when it's well below zero.

 

[Extreme1]

Mine croaked a few years ago, before the parts were available individually (I had to buy the whole assembly!! )



Anyway, it was bad in the winter. Although it always ran, it ran with very low power when the temps got into 20's. The milage was very bad too.

 

[BroncoMarc]

Where did you find the parts individually? Dodge want to sell my friend the whole assembley for about $250.

 

[Jeff H]

I was at the hutch auto salvage. They had a one ton minus one diesel truck. In the seat was a high pressure injection lines. Also a fuel heater. Any interest? Maybe could find other goodys too. I was looking for something else so I didn't spend much time looking through it.

Jeff H

 

[dremelts]

Here is a thread with some info on part numbers etc. for the fuel heater components.





https://www.turbodieselregister.com...p?threadid=33109&highlight=diesel+fuel+heater



When mine burned up last winter I bought all the components but found that I only needed to replace the wire harness and the thermostat - the heater element itself was OK.