OBD2 blowing fuses
OBD2 blowing fuses I have been searching and can't seem to narrow this down any further. I just bought a 99 Camaro SS. The OBD2 port will not work. I checked the fuse and it was blown so I replaced it and it blew the fuse as soon as I plugged in my code scanner. I removed the scanner and replaced the fuse and it blew immediately (without the scanner connected this time). So then I disconnected the cig lighter plug and the 12V accessory plug. Again, I replaced the fuse and it blew immediately. I took the knee bolster out and looked at the wiring under the dash and can't see anything spliced in or out of the ordinary. I am at a loss. I know it is common for the cig lighter to do this but they are disconnected. At this point this thing melts the end of the fuse and blows it as soon as I insert it. What else could it be? Any help would be greatly appreciated.
Also the tachometer intermittently works. Out of 15 times it didn't work twice at startup but began working after driving for a few miles. I figured it was voltage related or a grounding issue.
Also the tachometer intermittently works. Out of 15 times it didn't work twice at startup but began working after driving for a few miles. I figured it was voltage related or a grounding issue.
I am not great at electrical troubleshooting but I took a multimeter and did some checking. Incoming power was good at the fuse location. I checked the non powered leg at the fuse box and I have continuity to ground. I checked the obd2 port and have continuity from pin 16 (battery power) to pin 5 (signal ground) but not from pin 16 (battery power) to pin 4 (chassis ground). What is the difference between chassis ground and signal ground?
I am not great at electrical troubleshooting but I took a multimeter and did some checking. Incoming power was good at the fuse location. I checked the non powered leg at the fuse box and I have continuity to ground. I checked the obd2 port and have continuity from pin 16 (battery power) to pin 5 (signal ground) but not from pin 16 (battery power) to pin 4 (chassis ground). What is the difference between chassis ground and signal ground?
You could have a short to ground in the wiring harness or you could have a bad cluster or module. Chryslers are really bad about it but GM not as much.
First thing I would do is get a wiring diagram for everything on that circuit and look for the most obvious things.
It's also possible that a wire for that circuit has burned or "melted" into another circuit.
I had a Toyota SUV that kept blowing the wiper motor fuse. After some searching I found the fuel pump was going bad and had melted the entire body harness and was grounding/shorting out the wiper motor circuit.
If you feel you are capable of finding the problem yourself with some help let me know. If you know it's over your head(which is fine, electric problems can be difficult" then take it to a competent shop.
Here shortly someone will be in here to tell you to swap out a bunch of parts till you find it....Waaaiiiiit for it.
Seriously though, shoot me a PM or keep us updated in this thread.
J
Thanks for your reply. I did some more checking. I unlpugged the ODB2 port and wiggled the wires and tried another fuse. It did not blow the fuse this time. I reconnected the cig. lighters and they had 12V to each one. I then hooked up my code scanner and it powered on and I started reading the codes and it cut off in the middle of downloading the codes... I checked the the lighter port had 12V and they were still good. I moved the reader around and it came back on so I know that the issue is very near to the OBD2 port. I kept wiggling the plug and the reader would go in and out. I am thinking that it is the OBD2 plug. I went and cut one off of another vehicle and will replace it tomorrow. I will update this post once I know more. Maybe this will help someone else in the future.
In the event that this post may help someone in the future, I found the problem... I replaced the OBD2 port and I saw a spark when connecting my scanner this time. The metal bracket that the OBD2 port is mounted on was digging into the wire loom above it and shorting against one of the wires. It wasn't actually touching the wire, but it has in the past because I can see where the insulation is rubbed off of the wire. This wasn't easy to see and I had to spread open the wire loom to see the offending wire. I made sure to wrap the wire in electrical tape and then the entire loom. I also sliced open a piece of vacuum hose and ran it around the perimeter of the metal bracket to keep it from happening in the future.
