Troubleshooting Trailer Lights Not Working With 2019 Chevy Express Van
Question:
I have no turn signal or brake lights on the van and trailer I have running lights and clearance lights on the trailer and truck the left side works properly the right front van turn signal works properly I also have no hazard lights on the trailer or the van on the rear
asked by: Brad C
Expert Reply:
I can give you a number of troubleshooting steps as it seems like there are lights everywhere not working, though it was difficult to differentiate exactly which ones so here the steps you'll need to take.
The first thing to do is take a look at your owner's manual to your 2019 Chevrolet Express Van's owner's manual to locate any trailer fuses or relays and ensure they are all there and in working order. If they are, in order to determine the specific problem you will need to purchase a circuit tester if you do not have one - the very handy Cordless Circuit Tester # PTW2979 would be my strong recommendation due to how easy it is to use - and test the connector on your vehicle after disconnecting it from your trailer. Check the wiring going into your harness from your tail lights to see if those wires are carrying the correct signals, if not then the issue is with the vehicle wiring.
If the signals going to your harness are okay, you'll need to test the signals coming out of the harness, and if they are correct then your issue is likely going to be with the trailer side wiring. You will also want to check both your vehicle and trailer connectors for corrosion, which can be green or white in color. A build-up of corrosion can interfere with the signals getting through the connectors so if it is present you are going to need to either replace the plug or clean the corrosion. You'll also need to make sure your grounds are attached to bare metal surfaces and free of any paint, dirt or corrosion.
I have added links to a pair of help articles on trailer wiring, including a troubleshooting guide which I highly recommend taking a look at. Additionally, I also highly recommend using Dielectric Grease for Electrical Connectors # 11755 to help prevent any type of corrosion in your connector; using it will increase your connector's durability and extend its lifespan.

Products Referenced in This Question
Dielectric Grease for Electrical Connectors, 2 oz.
- Accessories and Parts
- Trailer Wiring
- Wiring
- Dielectric Grease
- LubriMatic
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