RAMRODD

I am installing my Pacbrake my question is on the ecm it says locate pin #42(50 rear connector) What does pin 42 do???
The instructions also say to use Pin 39 for the ground. Why do I have to ground threw the ECM??
Any one install the ECM bypass system??

Sandaholic

I'm sorry that I don't have any useful information on this. I just had to chime in and say that I hate funky instructions! Why would you ground through the ecm? I've never heard of that. Good luck.

cbrahs

I do not know what those circuits are but alot of the newer rigs, the ECM grounds the circuit to operate it. is it a true ground or one operated by the ECM? If it says to do it, probably should do it.

RAMRODD

My goal is to operate the exhaust brake by a switch on the shift lever. I already have the swith it is a BD and I used it on the old banks brake. I don't care about the brake turning on when the truck is cold or when I step on the pedal it disengauges. To do this I shouldn't have to go threw the ecm.
Pacbrake has a ecm bypass kit so it can be done, just trying to figure out how!! Customer serving isn't open on the weekend.

CD in NM

While someone with more technical knowledge about this probably will have the better answer, I believe that the ground is important to complete a circuit that operates the brake. Our 2006 trucks are the first to have brake programming standard via the ECM.

I installed the switch on my shift lever, the ground would have been made via the ECM plug pin #39 whether you install the clutch switch or not. I installed the clutch switch, it is a really nice feature. I drove someone elses truck that had the PacBrake w/o the clutch switch, glad I did that drive first, it was the impetus to installing the clutch switch.

If you want to use your brake with the cruise control you need to go through the ECM. The brake does not turn itself on for warmup when it is cold, you turn it on, what it really does at warmup is turn off when the engine reaches 170*. I like the feature, when it turns off that's my signal to go. I do not drive my truck stone cold, I prefer to warm it up. If at startup it goes straight to the 1K idle, I turn on the brake, when it kicks out it's then warm enough to drive without it taking forever to get fully warm in cold weather.

There are schematics on PacBrakes website in their technical information that show the installation for the bypass, you have to sort through the different installation manuals, but it is there.

CD

Fisherguy

I grounded a pin on my ECM for the high idle feature, can't remember what number but there's lotsa threads on it.

Harold-Pacbrake

By useing the Ecm, the ECm knows when you are requesting the exhaust brake thus working in place of a throttle switch, therefor if you/someone dricing the truck forgets to turn the switch off the ECM will automaticly cut the brake off. You have to run ether the The ECM or the ECM bypass (throttle Switch for the safety of your vehicle and its drivers.

Fisherguy

Harold,
I was just looking at your Pac Brake website, if a person did not want to tap into the ECM he could buy your optional throttle position switch instead, right?

I'm looking into getting a clutch switch right now, if you're at the shop in Surrey I live right close, can you PM me with a price please? (it's not on your website)

DieselBoy20

The ECM wiring on the pac brake is simple, your not gonna hurt anything...just unhook your batteries and use a hex key to remove the connector off the block and find the pin number and push the pin wire in until it kinda clicks and doesn't pull out at all, it will stick in there. Put the ECM connector back in and its done. Not scary at all. I installed my brake myself also.

CD in NM

I just used a pair of forceps to grab the pin plug an pull it out. Then inserted the ECM pins STRAIGHT into the holes, they snapped into the pin locks, all done. You can do this without disconnecting the battery and removing the connectors. Very easy to do, just take your time, make sure you are going straight into the backside of the connector and they will go in without a problem.

CD

Fisherguy

That's always been the problem for me, taking the plug out. I can never get hold of it with anything and always end up unbolting the plug to push it out from behind...

RAMRODD

I didn't want the 2 1/2 second delay from going threw the ECM. I did the grounded pin for the high idel so no big deal as far as doing it again.

All is good now I figured out how to bypass it on my own and it works off of my BD switch on the shifter. Brake works great couldn't be happier!!

Festus

I have ~1/10th of a sec. delay going through the ECM. Just as good as a bypass as far as I'm concerned. Many OTR trucks I've driven don't cut in that fast with the sensor on the go pedal.

Fisherguy

Me too, definitely not 2½ seconds.

Festus

Not to hijack the thread, but Fisherguy, have you ever had your PacBrake only cut in half way or less randomly?

Mine was doing in consistently for about a week and a half. It would work as normal on warm up, but then do this after starting out driving and would either only engage half way or normally in a completely random pattern. However, last time out, worked like a champ. I can't figure it out.

Lots of air pressure, drained tank(no moisture), nothing is loose, well lubricated. I sent an email to the tech guys at Pac through their website - no return anything yet.