Hey @grantwest, how are you running wires up there? I don’t see anything visible in the pics.
The unit is installed by toggle bolts they are a threaded insert looking bolt.
The unit has 2 places where your wire loom can exit the unit and then you drill into the Overhead pillar and run the wire loom down the pillar and the wires come out by the base of the window.
sweet. so the pillar is an unobstructed run. good tip. i want to hide my backup camera/rearview mirror camera wires better and this will be perfect.
You can run the wire backwards to the rear of the car for your back up cam.
I tried to sneak the wires in between the windshield and the pillar and it wasn’t enough room. I’ll just pop a hole in the pillar and run it inside, I just didn’t want to do it and find out it had dividers or impediments. thanks!
So……………anyone of you willing to share your wiring diagram for the stereo install? Anyone install a second 12v battery to power the stereo so as not to drain the GEM batteries?
Thanks for sharing!
@grantwest - could you share more detail on the type of toggle bolt you used to install here? I’m trying to avoid the epoxy guidance on installing the overhead unit. Curious what you did here as I like the idea of being able to get into the console box if needed instead of having to strip off the epoxy or work directly through the stereo or speaker openings.
No problem. The Way Gem does it from the factory it’s Glued. Now I wouldn’t want to ever have to take a factory one down cause the glue removal process would be a pain.
The bolts I used are called SEX-Bolts. Yea I know crazy name
ZXHAO M5 Chicago Binding Screws Sex Bolt Barrel nut Barrel Bolt Post Screw 100pcs (5x10) https://www.amazon.com/dp/B07SJRLPQ7/ref=cm_sw_r_cp_api_i_xEw0DbAT0K2YT
These are NOT THE EXACT ONES I USEstrong text**** I just posted the link to give you a idea. The exact thickness of Sex bolt you will need may vary and you will just have to use your own judgment on what size.
I can give you a tip. The roof on your Gem is curved. The stereo console is Flat. You need a buddy to help you install it so it comes out good.
What you need to do is (while the overhead console is empty and light) place it up on the underside of the roof. Push up on the console so it bends and forms and SITS FLUSH to the underside of the roof. Then when it’s centered on the underside of the roof drill the 2 hole’s threw the Console and up into the roof that would be on the edge that would be in directly in the middle. This will allow you to mount the console flush to the roof and cause it to flex/form to the contour of the underside of the roof. Then Drill your holes for the out side edges ( I’ll draw you a diagram)
1 Like
I saw all the talk and links for Bluetooth amps and almost pulled the trigger but then realized I have portable Bluetooth speakers which really just need clips to hold them and 2 will pair to give stereo.
Not going to boom boom down the street but I was never a fan of club-music. 
Nice looking overhead install though.
I’ve gotten around to adding a new stereo system that came with a backup camera. Unfortunately I have an older 2001 GEM that doesn’t have backup lights to run the camera system. I figured I could just tap into the forward/neutral/reverse switch but when I pulled voltages from the switch I read 20V in the “on” state and -42V in the off state. I thought everything on the GEM was +72V or +12, so was a little surprised. Everything on the car works as it should, including the backup beeper, so I presume there isn’t a short anywhere, but the stereo needs a clean 12v on/off signal to function properly. Works great on the light switch, which is 12V, but having the rear camera on everytime I drive at night seems less than optimal! Has anyone installed a backup camera on an older GEM? if so any thoughts on how to get around the weird voltages?
what is the voltage at the beeper ?
The beeping seems to come straight out of the main control unit so wasn’t able to find the beeper and measure the voltage across it.
1 Like
I added a separate “smaller” battery between the frame rails under passenger seat. I use that battery for the power and negative for this system. It does not draw off dc/dc converter (two amps, tv, backup camera) the purple wire under the dash that is for cigarette lighter I use as the remote wire.
Thanks Bundcur, what year is your GEM? I have a 2001 and there definitely isn’t a cigarette lighter. I’ve been playing around with arduino chips and sensors lately. I’m going to see if this weekend I can hook up a full wave rectifier and a voltage split circuit to change the -40v (off) 20v(on) signal coming from the backup switch into a +3.6v (off), +1.8 (on) voltage signal that I can read with a cheap arduino board. Arduino boards don’t like negative voltage. If the voltage is below 2.5 volts to the arduino (representing a 20V backup switch “on” state) I’ll open a relay that will let 12v flow from the ignition to both the stereo controller and the backup camera. In theory this should work as long as there is enough current flowing from the switch to be read by the arduino. I probably should measure that, but I’ll probably just hook it up and see what happens. Should be an interesting experiment. If it works I’ll post more details about the stereo/camera system, arduino code, and wiring details so others can consider this solution also. I really like the idea of a backup camera as it is hard to see how close I am to vehicles behind the car when trying to fit into tight parking spaces at the beach, which is my primary use of the GEM. If it doesn’t work, well I guess nobody will care about the details 
It’s not a good idea to add leakage to ground from the 72v system. You will get weird voltage readings and possible problems.
For anyone needing a 12v “reverse” source, connect an isolated dc-dc from R switch and B-.
Or use an existing 12vdc source through a NO relay.
Connect relay coil from R switch and B-. Use a diode to isolate from controller. Cathode to p5.
If trouble finding a 72v relay, a 120vac coil will work.
That make sense, thanks! just ordered a 72v isolated DC/DC and will transition to that. Much more straight forward.