I fitted a rear camera to my car headunit using all supplied fittings. Everthing worked fine for a few months, then it stopped working. I just get a blank screen when shifting to reverse, so suspected power wasn't getting to the camera. Checked voltage today from rear reverse light (source) and it is showing as 10 volts but as soon as I connect the camera to that cable (which is on a 50cm lead) voltage drops to 4V. Camera works fine on another car. Any ideas what might be causing this power drop ?

Thanks.... if I run a temporary wire direct from the battery - ve the camera works fine. I was taking the negative/earth off the chassis and the +ve off the reversing light. How to fix this - is it ok to take the -ve also off the reversing light ?

Clean up the dirty ground connection and you will be good to go.

 

Do you also have issues such as your tail light going out when you apply the brakes?

 

 

I was taking the earth by fixing a connection through an existing hole on the body behind the taillight (thinking good waterproof area). I scratched off a bit of paint at that connection point but still down at 4V. I think I need to take the earth off the frame (rather than the body) so will give it another go. No issues with tail lights.

20 hours ago, regedit said:

I was taking the earth by fixing a connection through an existing hole on the body behind the taillight (thinking good waterproof area). I scratched off a bit of paint at that connection point but still down at 4V. I think I need to take the earth off the frame (rather than the body) so will give it another go. No issues with tail lights.

Where is the tail or reversing lights earth connection....?

Want painless wiring for your accessories ? Install two Buss bars - one + one - direct to battery with a fuse.

Run all accessories off those two. Got a high amp draw device - use a relay from those same bars. Never touch the factory wiring harness. All's well.

Problem was solved by taking the negative off the reversing light. 

3 minutes ago, regedit said:

Problem was solved by taking the negative off the reversing light. 

Glad I could help...