Help! Safely removing heater

[Wantabus]

Hello all,

So Ive watched 10+ videos of others removing their heaters. My bus is a mini bird and I need some advice before moving ahead. 1999 GMC stv 6.5 detriot diesel.

Electrical: how do I safely disconnect the wires from the heater. Even with the engine off these are still connected to the battery correct?

Heater removal: I plan to:
Drain coolant from pipes from underneath the bus
Connect the lines with a copper u joint to close the loop
Secure connections with pipe clamps

Please let me know if you would do things differently. I haven't even gotten to drive my bus yet, paranoid if frying something crucial.

Thanks everyone!

[Stngllhm]

The wires should only be live when the switch is on for the heater. You will need to find the fuse and pull it and disconnect the wires leading from the switch to the blower. I would pull the wires all the way out if they are easy to get to otherwise just clearly mark on both sides what they wear for and that they have been taken out of service. You will thank yourself later. As far as the coolant lines if you can take them apart in the engine compartment. The more of the old system you remove the less it can bother you in the future

[o1marc]

That switch can be repurposed and possibly use the old wiring in place