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Auxiliary switches 2019 Tradesman

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Reeder

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Hey Guys. Long time lurker.
I have read EVERY thread I can find on adding auxiliary switches/upfitter, etc. but I have one simple question. Don't beat on me...I know how many threads there are on this, but there is some conflicting information out there. Some of the info is year specific and I think that's what I'm confused about.

I have a 2019 Tradesman 3500 HO dually longbed 4x4. I love the truck. In retrospect I would have had the switches added at the factory. I need about four switches at this point but only have the basic switch panel with trailer brakes, exhaust brake, tow/haul. I would like to add the panel that includes auxiliary switches. BUT...I do not want to go through the can-bus system or add the upfitter wiring. I can't justify the expense simply to add a few switches. My plan would be to add wiring to the existing connector so I have outputs from the extra switches. I would add my own wiring to a relay-box to activate the switches. I am aware of the connectors, upfitter harnesses, relay box currently under the hood, etc. but have chosen to keep this simple and add my own independent systems.

So my question boils down to this....In a simple system, wiring straight to the individual switches (through the connector)...Do the switches GROUND upon activation and are they on/off?? I know in some past years this was the case. This way I could bypass the can-bus system, etc. This being a 2019, I'm not sure what the answer is.

Thanks guys!
 
Reeder said:
Hey Guys. Long time lurker.
I have read EVERY thread I can find on adding auxiliary switches/upfitter, etc. but I have one simple question. Don't beat on me...I know how many threads there are on this, but there is some conflicting information out there. Some of the info is year specific and I think that's what I'm confused about.

I have a 2019 Tradesman 3500 HO dually longbed 4x4. I love the truck. In retrospect I would have had the switches added at the factory. I need about four switches at this point but only have the basic switch panel with trailer brakes, exhaust brake, tow/haul. I would like to add the panel that includes auxiliary switches. BUT...I do not want to go through the can-bus system or add the upfitter wiring. I can't justify the expense simply to add a few switches. My plan would be to add wiring to the existing connector so I have outputs from the extra switches. I would add my own wiring to a relay-box to activate the switches. I am aware of the connectors, upfitter harnesses, relay box currently under the hood, etc. but have chosen to keep this simple and add my own independent systems.

So my question boils down to this....In a simple system, wiring straight to the individual switches (through the connector)...Do the switches GROUND upon activation and are they on/off?? I know in some past years this was the case. This way I could bypass the can-bus system, etc. This being a 2019, I'm not sure what the answer is.

Thanks guys!
Click to expand...
The switches complete ground. When you install the new factory switch bank that has the aux switches, you still will most likely need to use AlfaOBD to enable the switches to work.
 
Agree with Jimmy and AFAIK, the issue is the switches are not using a mechanical latching mechanism but are just a pulse signal to the BCM to set a state.

The BCM then uses the LIN bus connection to keep the switch latched, and control if it's always on with ignition cycle, or resets.

1620585623241.png
 
Brutal. That's kinda what I was getting. So it seems to me the bottom line is I won't be able to use the panel the way I intended. Does that sound accurate? Thanks
 
It sounds like you don't want to have to use alfaOBD to enable the switches. In that case they won't simply latch ground for an external relay like you would need.

I see you're in Colorado, and with my mystic orb I can see you're in the Denver area. There's quite a few members here, some have AlfaOBD, myself included. If it's feasible, I'd be happy to enable the switches for you once you have everything installed.
 
Hey Brutal. That's awfully nice of you! I appreciate it! I may have misunderstood before (sorry for seeming dense--LIN BUS is new to me)

So if I add the panel, add pins/wires to the existing harness (that I can connect to external relays), and "add" the functions with AlfaOBD, the switches will latch ground?

If that is correct, I'll order the panel and pins. I don't mind buying AlfaOBD as long as I know it's going to work.

Thanks again! You're much more knowledgeable about this than myself.
 
As far as I know, correct. You would just pick up the grounds in connector X/Y125A.

Since you have a diesel, you also already have the factory AUX PDC in the engine bay but would have to add all the wiring, relays, fuses, etc. to do a full factory AUX switch add.

See this post Jimmy made for pinouts: https://hdrams.com/forum/index.php?threads/aux-switches.97/post-28392

If you want to go the factory route, reach out to member @paulvi , he may still have parts and/or be selling custom wire kits.
 
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