maybe368

Hi fellas, It has been a few years since my truck has caused me to seek out help on this great forum. I have had quite a year involving health issues that have caused me to park the old girl for around 5 months. Everything was hunky dory when parked, but when I used it a couple of weeks ago, the brake and RWAL lights were on. It happened while sitting, any ideas? This is killing me. The other thing is my License plate lights don't work. I don't have 12 volts at the connector to the lights, but I do at the fuse. Can both be related to a fusible link? That seems to be the only common point between the 2, I Think. It all happened while parked, go figure , Any ideas?...Mark

j_martin

Not too likely to be related except maybe both might be caused by rodent damage.

Disconnect the parking brake switch and the vacuum switch (driver's side under hood) and the combination valve switch (under the MC) and see if the light goes out. They all set the brake lite, and that will set the RWAL light. Re-connect them one at a time till you find the culprit.

Don't know if a pickup would be the same as my '90 B350 van, but on the van if something plugged into the cigarette lighter blew a fuse, the brake light would come on. Stupid design, but it was what it was.

I believe tail lights and license plate lights are on the same circuit. Might be a dirty connector or mouse bite under the back of the box.

diesel402004

My abs light came on the other week and ended up being the taillight bulb. The bulb had some corrosion and was causing a short.

maybe368

Thanks guys, I'll give all that a try tomorrow...Mark

NJTman

on each side of the bed, behind the rear tires inside the frame rails up underneath is a connector that leads to the rear harness. When I had issues with my brick, I found that the 4 prong rectangular connector, which I assume is designed to allow removal of the bed with ease, on each side were corroded. I actually had to bypass the passenger side as it was so bad.

Not sure what yours is like as you're out of the salt belt, but it's another place to look when all else fails.

jimbo486

In regards to the license plate lights.... There is, at least on my truck and the 91.5 donor I had, a 2-way connector (plug) on the passenger side frame rail at the rear which supplies power to the license plate sockets. Might be worth a look to see if the contacts have corroded some or by chance, it became disconnected.

maybe368

Thanks, I have all of that harness out from that connector back and I have no voltage at that connector. The problem must be between there and the cab. Is it a possible light switch problem? I am close to just splicing the plate light straight into the tail light circuit, which is working fine....Mark

jimbo486

That would be just fine, Mark. That 2-way connector is spliced at the main harness from the running light circuit anyhow. Black/Yellow is the signal (+) and grey is ground (-).

You must not have a short anywhere since I don't see mention of the fuse blowing. It must be disconnected (or broken) somewhere between that 2-way connector and the firewall bulkhead.

Do the tail lights and other running lights work, if any?

bigragu

Know about health issues, as mine are more towards "physical ailments". December 11th, at high noon, I'm going to undergo my 3rd back surgery. No fusion, just a laminectomy discectomy. For the last 3 years I've been waddling around, falling on my face every so often, cause from my left calf to the entire bottom of my left foot, no feeling. Doesn't take much to role, the ankle and eat dirt...I've fallen stepping on an acorn. Surgeon man seems to be leaning towards bulging discs at the L3, L4, and L5 pinching off a nerve of some kind. Looking forward to the fix, and hope it works. No wrenching for me for 8 weeks, that is on the truck and the wife, LOL! Sorry I can't help you with your problem...what J Martin suggests makes sense to me, as I've popped open my hood to find a rat running off, and my under hood insulation torn off at some spots for winter bedding, I assume. With that said, and 8 weeks off from driving, you bet your butt I will be applying rat traps n poison bars under my hood

maybe368

I thought that I would close this out. The license plate light problem was that I had put the connector in an extra, identical connector that is near the same place and was unused from the factory. I plugged it into the other and it worked. I probably had no lp light since I replaced the bumper several years ago . The brake and rwal lights were easier, they went out by themselves. I am thinking that it was a low vacuum problem because it kind of fixed itself by degrees. It went out for a few seconds when I started the truck, but, it came back right away. Over a few days of driving, it went out and didn't come back. Man, I am a good mechanic ...Mark

mknittle

I love it when things fix themselves.

maybe368

Boy howdy, you got that right. I am a great mechanic (said in the voice of the rain man...Mark