I bought a Hummer 2 limo 2009. The AC stopped working and they traced that it's this thing enter image description hereenter image description hereenter image description hereenter image description hereenter image description hereenter image description hereenter image description hereenter image description herethat got burnt. We checked our local spare parts dealers and they don't know what it is, there is no writeup on the device. I bought the vehicle since February and this is November, I haven't fix this, please help.

  • Welcome to Motor Vehicle Maintenance & Repair! Any idea what the switch is supposed to do? What it's supposed to do if you turn it? Are there any markings over the switch on the outside of box? I can't quite tell if it is a rheostat type switch (scale) or if it clicks as it is turned (selective). In the top picture, there seem to be two boxes here which are of the same make-up. Are both boxes burned up? If not, that might clue you as to how this might be rebuilt (or built in the first place). Commented Nov 1, 2022 at 17:43

2 Answers 2


That's clearly not a "standard" item and based on its appearance, it appears to be a one-off or low-volume custom made device.

Tracing the wires to wherever they go may provide some additional clues to its purpose.

Also, you might see if you can track down the "coach builder" who turned the Hummer into a limo. It seems likely to me that it's something they added and they might be able to provide some information or assistance.

  • Thanks for your feedback, unfortunately i bought it used from someone, and the person had the limo for over 14 years. So there is absolutely no way of tracking the actual builders as the VIN is not in any record. I checked on reddit and someone suggested that it might be variable inverter (dc to ac low voltage) to supply control voltage to the a/c system, i'm looking into that.
    – Hither Joe
    Commented Nov 1, 2022 at 17:08
  • As I said, trace the wires to see what they go to. That might help identify its purpose. As it is it's little more than a box with charred remains inside.
    – jwh20
    Commented Nov 1, 2022 at 17:10

enter image description hereAfter contacting a limousine manufacturer I Finally found out that it's Fibre Optic Light Engine used in the hummer. I think the people that worked the car before, connected the AC control to the Fibre Engine, that's why after it got burnt the AC control is not working. Though the one used is an old model and can't find it anywhere. Thanks everyone for your input.

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