bypass parking brake 990hd

[Nealrap]

I'm stumped. Which wire do I need to ground to bypass the parking brake thing? I don't see the light green wire, but maybe it's that white one next to the blue one? (I'm colorblind and it's driving me crazy)




Or is it in this harness?

[dznf0g]

I believe you will need to trace the light blue and the purple/lt blue stripe wires back through the harness until you find the accessory 2 connector. Then determine, by examining the connector, which of those wires is connected to the light green park brake sensing wire.

[Nealrap]

I don't see lime green anywhere? I can't trace too far because everything is taped up so much.
I'd think there should be a port somewhere on the unit that I could just attach a wire and ground it? Why do my colors not match up?

[dznf0g]

Welcome to the world of upfitting and RV building. It is RARE that you will find matching wiring to the chassis. Follow the taped up/conduit-ed harness until you find a nylon (probably) connector. At least that is what your wiring diagram shows....the green wire should be terminated at that connector. Some dis-assembly most likely required.

[dznf0g]

BTW, I guess I should ask. Who's wiring diagram is that? AS, Benz, or the "AV" box manufacturer? Is it specific to the Benz chassis?

[dznf0g]

Upon further study, I am not at all impressed with this wiring diagram. It appears they are showing two different units' wiring on one diagram. SLOPPY work!

I am unclear if what I assumed is a connector in the harness is in fact a connector. It may be the plug which goes directly into the unit (your pic). If so, I assume you have the 990, because I see you have the voice control switch plugged in per your pic. That is only available for the 990. BUT......the 990 should have 3 wires in the plug. Your pic shows 2. Your pic shows colors that don't match. BUT, I did work in a wiring plant as a dyer and striper. It is not uncommon to find color bleeds for many feet after a dye change. I wonder if your light blue is really light green, and the purple/blue is really purple/white.

Disconnect the plug and use an ohmmeter between the blue(ish) wire and ground....then turn on the ignition and apply the park brake. The ohmmeter should read infinite resistance without the park brake applied and very low ohms with the park brake applied. That'll tell you that is the wire to ground.

What are you trying to accomplish? Camera functionality?

[dznf0g]

In your second pic, the wire does actually look pale green...pastel. And the purple/white does look purple/white.

[dznf0g]

Third pic has nothing to do with it...it is the two pack with the white plug.

[Nealrap]

Yes, it's a 990
I'm trying to bypass the parking brake, so I can type while driving, (or the passenger can).
I'll try that ohm meter thing. I think I have one here.
THanks!

[Nealrap]

The ohm meter trick worked. That white wire was the one, so I spliced in a little wire & ran it to a screw on the back of the unit & it works now.
Thanks!


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[dznf0g]

Welcome