2nd Gen Non-Engine/Transmission E-Brake & Alarm Gremlins

[Shelby Griggs]

Twice in the past couple of weeks after a hundred miles or so, the E-Brake (Jacobs) has failed to activate, nada. Shuting the truck off and restarting, it seems to work just fine. In fact the last time it happened, I could cycle the brake off and on just by shuting the key off and then back on, without even starting. I am thinking maybe the ECM?????? Seems to work fine for days at a time on short trips. It seems to be something with 2 hour plus run times.



Also recently the factory alarm has been going off when I unlock the doors with the fob. I thought maybe the batteries in the fob were weak, so I replaced those. The second time after that I got the same thing to happen. This does not happen all of the time, but is becoming quite frequent. I had the CTM replaced once about a year ago for essentially the same problem, except before I could not shut the alarm off, except to get above 20MPH. Dang weird.



Anybody got any thoughts on where to start looking? It is on my dime now, at 60K



Shelby

 

[Whitmore]

Shelby

Two things I can think of



First I would check/clean the connection to your ECM on pin #20, you are right that this is where the signal comes from that tells the Jacobs solinoid valve to activate.



Also I would disconnect the vaccumn line from the solinoid valve to the brake and get someone in the cab to run the switch and see if it is working.



I would point more toward the pin #20.



cheers, Kevin

 

[Shelby Griggs]

I think I might be onto a solution on the e-brake. Happened again yesterday several times on a 300 mile trip. One of the times, I definitely noticed a higher than normal idle speed, when I stopped to investigate. Probably about 100-150 RPM's too high (over a normal idle). I am thinking that either the ECM is not allowing a return to idle, or something mechanical is hanging up. What should I be looking for in a mechanical hang up? It still only appears to do this after an hour or so, so I am having a hard time visualizing how run time could affect something mechanically. ECM heating up and failing, yes.



Alarm problem has been intermittent, but was either related to leaving cell phone plugged in, or proximity to some other external problem at the hotel I was at last week. Will update if I figure either problem out.



Shelby

 

[Sregorb]

Also check out:

https://www.turbodieselregister.com/forums/showthread.php?threadid=37790

for more alarm info... .



Brian