Recently bought this E350 based Thor 19G and Im trying to install an aftermarket head unit. I bought the unit from Crutchfield and it came with what was supposed to be a plug n play harness but its incorrect. My guess is they sent a harness for regular E350 since they dont seem to really support cutaway/RV stuff. There are two separate plugs on the back of the stock head unit. One has all the speaker wires and 3 additional wires. One is a larger gauge all black wire that appears to be a ground. The other is White with a red stripe that appears to be 12V constant, per my test light. Not sure what the last wire is, its gray with a light purple stripe and does not show any power with a test light. When only this plug is plugged in the stereo does not work but the clock lights up so it definitely has power and ground. See pic below.



The second plug is smaller and has what seems to be all the control wires for the unit. Im trying to figure out what all these wires are but I cant for the life of me find a radio wiring diagram for an 08+ E series, let alone one specific to a cutaway vehicle. I attempted to poke all of these wires with my test light to see if any had power at any stage (off/acc/running) and I get nothing from all of them yet when I plug it in the stereo fires up. There is a raw wire also in this plug which is interesting. Can someone help me out with what is what? I really only need to know which of these wires is 12V ignition on and illumination but if I could get an answer for all of them it would be great!

 

These should be accurate....
Theres 4 more pages for the APIM/SYNC/Jack etc, but shouldn't need them with a aftermarket head unit..

 

Thanks @Hayapower these are almost the same as what Im seeing behind the dash. A couple differences are that I do not have the blue hot with accessory delay, violet/grey cluster illumination or the orange wire. Ive got the radio working but I essentially had to throw away the harness from Crutchfield. I found a 12V accessory wire to tap into but Im yet to find an illumination wire. Ive tested every wire going to every plug in the dash and cant get a single one to work. Seems crazy to me that Ford would have a different harness for the cutaway vehicles but I guess there is a reason, especially now that they dont sell them to the general public.

 

They do sometimes list 'Cutaway' in audio options, but 2017 did not.
What's the production date of your van?
You could always pull an illumination from the HL switch, but it certainly should be available at the connector.

 

So the date of manufacture of the Van is 11/2016. The date of manufacture for the motorhome is 12/2016 but it was listed for sale as a 2018 when I purchased it which is odd. From what I can tell based on the VIN it was sold as a 2017 cutaway. Maybe Thor started manufacturing it in 12 of 2016 and didnt finish for some time? I guess that shouldnt really affect the cutaway being manufactured 11/2016

 

Looks like I am in a similar situation: What did you end up wiring the stereo's red wire and the car's purple wire to?

Car/Stereo
Black & grey/ Black
White & Red/ Yellow(?)
Purple/?
?/Red

 

I dont remember off the top of my head and Im not going to be where the RV is until next Wednesday. Ill try to remember to check when I get back next week but if you dont get a reply here by next Friday or so, reply again so I get an email reminder!