Pulling DFM fuses

[03blackz71]

On the Trailboss forum some guys are pulling the DFM fuses to disable it.   They are pulling fuses 60 and 67.   All that did it have no issues or check engine lights.

 

I was thinking doing it but wanted to see if anyone here have done it to there trucks.

 

Here is a link to there topic

https://www.trailboss.org/threads/pulling-dfm-fuse.481/

[voided3]

You have my attention. I currently drive our truck in L7 to disable DFM, but that would be super convenient if pulling those two fuses works as then I could just put it in D.

 

I also would be curious for anyone with a '21 that was built without DFM has those two fuses present or not. If the non-DFM 5.3 and 6.2 trucks don't have fuses 60 and 67 from the factory, I would view that as a good sign that it's an effective method.

[haider320]

Just checked. I have 60 & 67 and DFM is not installed on my 21.

Edited December 19, 2021 by haider320

[voided3]

1 hour ago, haider320 said:

Just checked. I have 60 & 67 and DFM is not installed on my 21.

Interesting. I wonder if they leave them in there even if they aren't being used?

[kmeleon]

Great post, I didn't know about this. Pulled 60 and 67 and just took a short ride. It will take a couple of rides this week to determine. 

[WeGone]

I currently drive in L9 around town. I will definitely be watching this. Maybe someone with a scanner could try it to confirm it.

[NorthskyblueT1]

I am of the understanding that driving in any "L" gear/ driving in Manual Mode does NOT disable DFM.

 

This is a change from the AFM trucks, where selecting an L gear in manual mode would disable AFM.

 

Can anyone confirm this?

[voided3]

Just now, NorthskyblueT1 said:

I am of the understanding that driving in any "L" gear/ driving in Manual Mode does NOT disable DFM.

 

This is a change from the AFM trucks, where selecting an L gear in manual mode would disable AFM.

 

Can anyone confirm this?

Driving in L7 on the 8-speed or L9 on the 10-speed does disable DFM on the L84 5.3 or L87 6.2 with DFM.

 

Driving in L8 on the 8-speed or L10 on the 10-speed, however, does not; you have to lock out the final overdrive gear to disable it. Driving in L8 or L10 is the same as D on these trucks.

[kmeleon]

16 minutes ago, voided3 said:

Driving in L7 on the 8-speed or L9 on the 10-speed does disable DFM on the L84 5.3 or L87 6.2 with DFM.

 

Driving in L8 on the 8-speed or L10 on the 10-speed, however, does not; you have to lock out the final overdrive gear to disable it. Driving in L8 or L10 is the same as D on these trucks.

Correct

[kmeleon]

1 hour ago, WeGone said:

I currently drive in L9 around town. I will definitely be watching this. Maybe someone with a scanner could try it to confirm it.

I have a scanner but I'm not sure if there's something that we can monitor to show dfm.... Does anyone know? 

[03blackz71]

3 hours ago, haider320 said:

Just checked. I have 60 & 67 and DFM is not installed on my 21.

 

Thanks for checking.    I was going to ask if someone could comfrm that.

 

I bet they programmed it off.    They probably use the same fuse block as before and just leave the fuses in.

[Silverado4x4]

I can always tell when the DFM kicks in by watching the instant mpg on the cluster, when it kicks in on level ground and the gas pedal is kept in one spot say at 60mph the instant milage will jump to the upper 30s or so and soon as I push the pedal slightly down it will drop to the upper teens to low 20s when the DFM disengages.

[Silverado4x4]

2 hours ago, 03blackz71 said:

 

Thanks for checking.    I was going to ask if someone could comfrm that.

 

I bet they programmed it off.    They probably use the same fuse block as before and just leave the fuses in.

It's programmed off due to no chip.

[Firehawk99]

Well I tried this and my truck ran like crap! It was shifting all wonky and started hard. I put them back in and it's back to normal. I have a 21 6.2 trail boss.

[kmeleon]

16 hours ago, Firehawk99 said:

Well I tried this and my truck ran like crap! It was shifting all wonky and started hard. I put them back in and it's back to normal. I have a 21 6.2 trail boss.

Strange, my 5.3 runs perfectly fine without them

Just waiting for someone to confirm if this actually shuts off dfm. I think it does from the way it drove last night but I want to know for sure.