Brake lights not working on 94 cheyenne
August 10th, 2022, 4:20 PM
#1
CF Beginner
Thread Starter
Join Date: Aug 2022
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
Brake lights not working on 94 cheyenne
brake lights and rear blinkers aren’t working on my truck. i’ve check all the grounds fuses the blinker relay i’ve replaced the headlight and brake light switch. idk what to do help me!!
August 17th, 2022, 12:19 AM
#2
Hello, there. You will need a good quality digital multimeter. I own an OTC. It is not cheap but OTC and Fluke make the good ones. Bust into your wallet and get one. They are accurate and you may need it for testing a low amperage circuit like your light circuit here. You will need to be able to test voltage that may be lower than the required voltage to run the circuit in the case of a poor connection. In other words a fractional voltage instead of zero, to tell you that the wiring is there but it is corroded at a connector or the ground is bad.
ONE way, and it is one of several choices, is to start at your sockets for your lights. If both sides are dead, you still should start by testing for voltage at the sockets for running, brake and turn signals. If all of those are dead, you need to manually trace your wires to the first connector that has all of those wires in it or there may be one for each side. But go all the way to that junction and test again on the tail light side of the plug by putting probes into the bottom of the plug for each lead, see if there is voltage. Next check the battery side of the plug. Keep going until you find voltage. This is assuming you have already ruled out fuses.
Having all three functions not working points to a common area where there is a problem, and most likely it would be a connector not connected, damage or corrosion that affects all the leads in a plug containing all of those leads. If you replaced the headlight and brake light switches and the blinker relay, verify that the feed wire has voltage for each of those accessories. Have you done that? I assumed above that you have. For all three of those new items to NOT send a signal to your tail lights, you have a common voltage feed issue, and again you have to painstakingly trace one wire at a time back to a source of power such as the panel on the firewall that collects power to distribute it to places like the fuse panel. Some recommend starting at that panel and working your way toward those relays and switches. I suggested working the other way. Either will work but if you start at the end you can catch it at the earliest place if it indeed is a bad harness connector.
ONE way, and it is one of several choices, is to start at your sockets for your lights. If both sides are dead, you still should start by testing for voltage at the sockets for running, brake and turn signals. If all of those are dead, you need to manually trace your wires to the first connector that has all of those wires in it or there may be one for each side. But go all the way to that junction and test again on the tail light side of the plug by putting probes into the bottom of the plug for each lead, see if there is voltage. Next check the battery side of the plug. Keep going until you find voltage. This is assuming you have already ruled out fuses.
Having all three functions not working points to a common area where there is a problem, and most likely it would be a connector not connected, damage or corrosion that affects all the leads in a plug containing all of those leads. If you replaced the headlight and brake light switches and the blinker relay, verify that the feed wire has voltage for each of those accessories. Have you done that? I assumed above that you have. For all three of those new items to NOT send a signal to your tail lights, you have a common voltage feed issue, and again you have to painstakingly trace one wire at a time back to a source of power such as the panel on the firewall that collects power to distribute it to places like the fuse panel. Some recommend starting at that panel and working your way toward those relays and switches. I suggested working the other way. Either will work but if you start at the end you can catch it at the earliest place if it indeed is a bad harness connector.
Thread
Thread Starter
Forum
Replies
Last Post