LB7: DSP5 and A/C issues

[MMLMM]

I thought this was worked out....

I tuned a truck and upgraded the OS, tune is perfect, A/C doesnt work.

So I tune it with his OS, but I get fuel pressure issues in the tune, but A/C works.

Now I build a DSP5 tune with his stock OS, tune is back to working great, but no A/C , It doesnt make sense as I used his stock OS to build the DSP tune from.....

I know that there was some issues like this awhil back, but I thought they were worked out...

Heres a kicker. buddy here who I built a DSP program has the same OS, I flash in this same tune that has A/C issues, and it works fin in his truck.

The problem truck only does this with the DSP switch installed and DSP programming.

I am working on building DSP tune from the OS that worked, but was wondering if anyone had ideas, thanks.

 

[Trippin]

After you load the DSP5 tune and find the A/C doesn't work, try flipping the DSP5 switch and see if the A/C compresser kicks on.

 

[MMLMM]

After you load the DSP5 tune and fine the A/C doesn't work, try flipping the DSP5 switch and see if the A/C compresser kicks on.

Thanks Guy,
Tried that too, doesnt work in any tunes at all. The tunes all switch fine and are solid, its just the A/C will not come on now. I started searching around and found this issue was common awhile back, and I have built 18-20 LB7 DSP tunes and this is the only truck with the issue, lol

This is really odd, lol. At first I figured it was an OS issue. I am at a loss right now. Going to try a new tune tomorrow and see what happens.

 

[EFI Support]

Mike, we are not aware that it was a common problem. We know that using someone else's stock tune can cause A/C issues, but were not aware that using the stock tune from the truck for DSP also caused an A/C issue. Can you please point me to those discussions so I can follow it up with Ross?

When you do the DSP upgrade check the segment part numbers are the same as the stock tune.

Cheers
Cindy