Community Forums

Deerhunter · 12-10-2014, 05:04 PM

I have an 03 DSDP. When changing the chassis batteries I notice a 2 wire harness that connected directly to the battery. Believing this was from the solar panel, I didn't hook it back to the battery.
When I tried to start the motorhome the engine would turnover but not start. I hooked the ground & positive wire from this 2 wire harness back to the battery and the engine started. The wire is either size 12 or 14 with a in line fuse.
Does anyone know what this harness relates to? I thought it to be just an add on and not a factory installation.

Monacoach · 12-10-2014, 06:41 PM

Probably the computer. I have that wire to as probably most coaches do.

dennis45 · 12-10-2014, 07:46 PM

I believe the wires you refer to is the one connected to the Far Neg Terminal of the chassis batteries. I have inadvertently left this one off during a battery service and had the exact symptom you describe. I'm not sure but I believe it is a direct ground for the Engine Management System. Was a bit of a head scratcher before I realized my error.
Pardon me for the upside down pic. It's an iPad thing that has me stumped.

"007" · 12-10-2014, 08:36 PM

I wouldn't try to second guess why or what they are for, they need to be connected to start the coach.
Newmar will add wiring that does not come from chassis MFG stripped down chassis and adds systems such as the Bird System for keeping all batteries charged in your coach.
The small solar panel on roof is to keep the parasitic draws off your chassis battery, ECM,TCM, from draining when no shore hook up is present.

wa8yxm · 12-11-2014, 07:15 AM

On the chassis battery there are often two wires.. The big one runs to the starter (And perhaps the isolator solenoid/boost solenoid)

The smaller one actually runs the chassis, it feeds power to the ignition dash, computer, and other controls, this is your main power wire to everything OTHER than the starter (On and jacks on a motor home)

On some vehicles this wire is connected to battery terminal on the starter solenoid, on other vehicles it is connected to the battery itself, but either way it is the main power lead for everything OTHER than the starter (on a car or small truck) or, Starter, isolator/booster, jacks on a motor home.

Deerhunter · 12-11-2014, 08:16 AM

Thank you all for your comments. I also noticed that when this small wire harness was not connected everything on the dash instruments worked except the volts.