2003 Allegro Bus Trailer Brake Wiring

[dwjones125]

I have a 2003 Allegro Bus and am trying to install a trailer brake controller, Does anyone know if it is prewired for controller. If so do you know where to find it?

[Pigman]

Don't know about the 03's, but the 08's on a Freightliner chassis have the wiring behind the instruments. Tiffin used the underdash plug for other things, so you need to do a bit of wire splicing. I'd call the Tiffin Help Line and ask how they did the 03's. If you need it I can give you the wire colors and plug arrangement on mine.

John

[Cruzer]

2003s are prewired. It's connected to the trailer lighting socket on one end and the other end is hanging somep0lace underneath the dash. It should be labelled but there's lots of wires under there so it'll take a bit of hunting.

[ERG Richard]

Are the 07's the same as the 08's on the Freightliner chassis when it comes to the trailer wiring?

[Pigman]

Richard, as far as I know the answer to that on the Freightliner side is YES. I had an 05 Bounder and now the 08 Tiffin and they were the same. Tiffin did different things with the plug than Fleetwood did and of course hid it in a slightly different place behind the dash. Different coach makers also stow the circuit protection for the plug lines in different places too, but the general idea is the same and Freightliner does it the same way. Coach maker hides the box in different compartments.

John

[ERG Richard]

Thanks, John. I had a quick look under the dash and I couldn't see any loose wires. There was a look of what looked like red and white wires taped together, one of the whites had a label that said "12 V Ground". What were the colors I should be looking for? Also found a 5-conductor plug, no chance that's it, could it be? Or is that too easy LOL.

[Pigman]

Richard, This is the info I have for Freightliner chassis with MMDC data systems. Tiffin has a habit of hooking things to the plug so in my 08 there's already a plug. When I needed to use some of the lines I had to do a bit of splicing. This is the best info I have on wire colors and the plugs

John


MMDC TRAILER TOW PLUG CONNECTORS
CONNECTOR UNDER DASH (BODY BUILDER TO LOCATE)

Plug port Color Description
A R-W Brake signal from Foot
B BRWN Lights
C R-W Brake signal to Tow Plug
D R 12 volt power supply
E BK Ground
F Open Unused

AT REAR OF COACH
CONNECTOR ON THE BACK OF THE TOW PLUG ( 10 PIN )
1 EMPTY
2 DRKGRN Right Turn Signal
3 DRKBLU Back UP Signal
4 PK Ignition Signal
5 BR Running Lights
6 EMPTY
7 R-W Trailer Brake Signal
8 BK Ground
9 BK Ground
10 YEL Left Turn Signal

[ERG Richard]

Thanks, Pigman, your wiring codes were perfect!!

[CptnMorgan]

I have a 2010 Allegro Bay on the Workhorse W24 chassis and plan to install a brake controller. I have located the 12-ga blue electric brake wire at the 7-way plug and traced it to the firewall forward of the dash but can not locate it under the dash. I also found a 12-ga black and a 16-ga red wire in the same harness as the blue wire. These traced forward with the blue wire until I got to the front axle and then they split off some where. I initially assumed that the black was for charging the break away battery on the trailer and the red would be the brake light wire needed for the brake controller. In addition to the electric brake wire and the brake light wire, I need a 12-volt 30-amp connection and a heavy ground for the brake controller. Can anyone provide any advice? Other than the electrical brake wire coming from the 7-way connector, is my coach include any other prewiring for the brake controller?

[Pigman]

Cptn, The wiring for the trailer controllers is furnished by your chassis maker based on what Tiffin requires in their contract. I'd call the Tiffin Help Line during normal business hours and ask them what the wire colors to the plug are under your dash. In the Freightliner Chassis, Tiffin put a plug into the trailer connector to power some things under the dash. I'd guess they'll have done the same in the Allegro, so don't look for an empty plug. The one you're looking for will be a 6 pin black plug with one port not used. Tiffin should be able to tell you what color wires are on the chassis side, and if you push them they should be able to tell you what colored wires they plugged in on their connection. Once you find the plug, it'll just require a bit of cutting and splicing but the ground, and power furnished will be sufficient. Ask them where the fuses for it are as well. Sometimes those are a bit hard to find too, and eventually you'll need to know where to find them.

John

John