Electrical
Thread Starter
5th Gear
Joined: Apr 2018
Posts: 5
Likes: 0
Electrical
My reverse lights were not working, so I popped out the license plate surround. The bulbs were indeed blown, i replaced them and they are still very dim. Here's where it gets strange, always before when I put the car in reverse the HVAC blower would turn off. I assumed this was some safety feature. Since I changed the reverse light bulbs, the blower does not turn off. What is going on?
Melting Slicks
Joined: Sep 2011
Posts: 2,258
Likes: 543
From: Appleton WI
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
My reverse lights were not working, so I popped out the license plate surround. The bulbs were indeed blown, i replaced them and they are still very dim. Here's where it gets strange, always before when I put the car in reverse the HVAC blower would turn off. I assumed this was some safety feature. Since I changed the reverse light bulbs, the blower does not turn off. What is going on?
The dim lights could be a bad ground OR you could have a reverse relay. Do you have a MN6 Manual Trans or an Automatic C5??
The reverse switch (on the passengers side of the MN6/MN12 trans are well known to be problematic. If it goes bad, you wont have ANY reverse light operation when you actually shift into reverse. Its just a crappy ball bearing actuated switch that fails quite often. Take a resistance reading of the switch in the REVERSE (closed ) position. It should be very close to ZERO OHMS. If you read significant ohmage, just get another switch. Its very easy to change. You would have reverse light when the BCM commands the lights ON.
The reverse light circuit has TWO means of being operated. One is shifting into REVERSE and the other is operated by the BCM when the BCM commands the lights to be on. (i.e. when you unlock the car by the FOB (Options set for the exterior lights to come on). See if the BCM commanded reverse lights are bright of the same dim.
Do you have the correct series bulbs in the reverse lights??
Dim lights are most likely a bad ground or a bad relay.
Bill
