Hooking up backup camera in 1984 Vanguard

jrloucks wrote:
Well, here are some things to test:

1. Without the engine running, measure the voltage level on your class c chassis battery's terminals (this is the battery that starts the engine, not the 'house' battery). If it's the same (7-10v) as what you measured at the lights on the rear of your rig. You may simply have a bad or discharged chassis battery.

2. Start the engine (assuming you can) and again measure the voltage of your chassis battery's terminals. It should read 12v+ indicating the engine's alternator is charging the battery/system properly. With the engine still running, again measure the voltage level at the rear lights. If the two voltage measurements match (12v+) then this may also result in your back-up camera now working. (Again you may have a bad or discharged chassis battery.)

3. However, with the engine running, if you measure 12+ volts on your chassis battery and still measure 7-10v on the rear lights, that tells me there is a short or poor electrical connection on the rear lights somewhere. This is usually the result of a poor chassis ground connection. You can confirm a chassis grounding problem by connecting one end of a temporary wire to a good chassis/frame ground point and again measuring the voltage level at the rear lights using the temporary ground wire as the ground (negative) connection point. If the voltage level improves (12+), then you'll need to check all the ground connections on all the rear lights. Look for corroded screws, oxidation on bare wires and fix accordingly.

Thanks for these suggestions!

The chassis battery is running full at 12.5V. I believe I tested them with the engine running before but can't be certain so I will check again. Might be a ground issue. I'll bring this info to my friend who is helping me out and we'll test some things out. I appreciate your help!