Help With Identifing Some Items Under Dash

[Dick Simonis]

I was poking around under the dash for the first time and found several items that I have no idea what they are.

First is a round plug just hanging there with 4-5 wires.  One wire goes to what looks to be a vacuum switch.  The plug is hand labeled PAC C-12.  I did try to attach a pic.

The second item is a push button with 2 heavy gauge wires....~12 or so.  It also is just hanging under the dash but I have no idea if it's a momentary or what.  I did not succumb to the urge to push it as,  for all I know it activates the self destruct timer.  In the attached pic it's visible in the lower right.

If anyone has any thought, I'd be glad to hear them.  Meanwhile I'm heading back under the dash.

Dick

[Dick Simonis]

I'm adding an additonal item to my request for assistance.  This one is a small multipin plug that is on the left hand side and looks like it was attached to something that may have been removed.  The pic makes it look a lot larger than it is in actuallity.  It's probably .75" X .50".  It and the associated wires are coiled and tied up.

[Jerry Carr]

Hi Dick,
 I am sure one of the folks with all the smarts will give you clear advise, but I think the black button is an over ride to the entry door combination, I have never use this button but on our old coach I recall having used for this purpose  

[Dick Simonis]

Hi Dick,
 I am sure one of the folks with all the smarts will give you clear advise, but I think the black button is an over ride to the entry door combination, I have never use this button but on our old coach I recall having used for this purpose  

Thanks for the tought Jerry but our coach doesn't have the entry door combination lock.  Back to the self destruct timer???

[Joel Weiss]

The previous owner told me the push button somehow reads out fault codes on the ABS system, but I don't know where they are displayed.

[Edward Buker]

This is the optional passenger seat eject button which is to be used when all else fails..... it fires the rockets in the seat base once the fins are deployed. If you hit the button twice it enables the parachute recovery system....use this option at your own risk.

Later Ed

[Roy Warren Co-Admin]

Ed,
I really like your answer, but I think the real use of the button is for the keyless entry system.  You will use it if you want to change the entry combination and set it to your key fob.  At least that is what the button I had to use to set my key fob looked like.

[Bill Sprague]

I once had some Cummins engine issues and the Coburg, OR Coach Care tried to plug a laptop into a connector under the dash and to the left of the steering column for trouble shooting and code reading.  After some frustration with adapter cords, they gave up and found a different spot nearer the engine.  

[Tom and Pam Brown]

If might be the pacbrake connector if so equipped.

[Dick Simonis]

If might be the pacbrake connector if so equipped.

Would I have a pac brake as well as the jake brake.  It does say pac on it with one lead going to a vacuum switch.  No idea what the vacuum is used for.  Unless it's actually an air solenoid....I thought vacuum now I'm not sure at all.

The push button still remains unpushed until I get a better idea of what it is.  Joels thought about using it to display error messages is good but I have no digital display so I'm up in the air in that one also.

[Gerald Farris]

Dick,
"Pac Brake" is a name that is commonly used for exhaust brakes, although the Pac Brake company is not the only manufacturer of exhaust brakes. The Pac Brake company also manufactures compression brakes. Compression brakes are commonly called a "Jake Brake" because the design was developed by the Jacobs Vehicle Systems company and originally called the Jake Brake or Jacobs Brake.

Your coach has a compression brake (AKA Jake Brake) and it does not have an exhaust brake (AKA Pac Brake). There is a possibility that the "Jake Brake" on your coach was made by the Pac Brake Corporation.

The gray round connector that you had in one of your pictures is a diagnostic link connector that is used by technicians to read data from the transmission or engine computer. I can not tell which system it accesses from the picture.

Gerald

[Edward Buker]

Dick,

The photo of the coiled up wire that looks like it was from something that was removed may be an audio system connector. If the wires all look like they are similar and they sometimes have a polarity tracer on them which can help with the identification. You could look and see if they have any coupling to any of the current audio equipment in the coach further up the harness. If not, there may also be some labeling done on the wires if they are part of the original coach harness.

Regarding Gerald's comment on the grey plug under the dash. If it is tied to a common communication buss like the one in the service compartment in my coach it could have access to both the engine and transmission ECUs. I used to think that the one under the dash was likely for the transmission and the one in the rear service bay was for the engine. When I went in to have my Jake reprogrammed they brought out a computer set up for CAT engine diagnostics and programming and checked those menus first and then they used a second computer from the same plug port that was set up for the Allison ECU and found the appropriate Jake parameter there (if memory serves me). The one port seemed to have both communiication options available. I do not know if the grey plug duplicates that or if it is functional at all but I thought that this info would be helpful if someone is trying to sort out where to get communications to the engine or transmission ECUs. If you have a rear service bay port it should be able to do both.

Later Ed

[Joel Weiss]

Despite the levity of this thread, I do believe the button is for retrieving the diagnostic codes for the Bosch ABS system.  I did some research and here is roughly what has to be done to read the codes:

• Depress and hold test button for three seconds. Indicator light will illuminate while test button is depressed.

After releasing test button, indicator lamp will turn off and blink code will be displayed. 1-1 will indicate no system faults
Press and hold the black button for 10 seconds to reset any trouble codes that were stored
[/list]

I think that for our coaches the light that will blink is the ABS light on the dash.  

[John Fearnow]

Dick, in June, after we left Mallard Creek, we visited BCS because our ABS light was on most of the time. Steve Wilson Of BCS dealt with the problem by getting a fault code from under the dash.  I am not entirely sure but I believe he plugged in a reader but have no idea if he pushed in the self destruct/passenger eject button.  But the analyzer worked as the code indicated was exactly the problem.  I'm sure Steve and maybe others at BCS could id any of the abs system parts.

John Fearnow
2002 Pat-Thunder