1997 ranger 2.3 2wd

my utility trailer blinker lights are very dim only when the head lights are on. I've hooked up one of those LED testers that plug into the tail light harness. This tester has the the 3 red LED lights that tell you if all three outputs are good. Anyway, when I turn on the blinkers the tester says they are good. when I turn on the hazard lights it says both are good. when I turn on the parking lights and the blinker or hazard lights the tester says the only good output is the parking lights. the two LED lights for the left and right blinker blink very very dim. I can only see them in the dark.

Please Help

 

things that I have tried.

I bought a replacement hopkins wiring kit because I thought mine was damaged. It came with the replacement piece that goes in the factory harness and out to the bumper. that didn't help.

I checked all the fuses, still no luck

I found a plug on the factory harness in the frame rail just in front of the fuel tank. I disconnected it and sprayed it with some contact cleaner and still not luck, starting to get frustrated!!

 

I don't know if I should feel dumb or not. I tried my little tester that plugs into the trailer light socket on the truck on my 2010 f-150 and both blinkers and the running lights work. it didn't work on my '97 ranger though. so, i've been trouble shooting for two days. I thought i would try the tester in my wife's '99 explorer since they are wired very similar, well the tester does the same thing in the explorer that it does in the ranger.

 

Have you checked the bulbs and sockets on the truck? If anyone of them has some corrosion, you have a poor ground/return in the circuit. Clean the sockets and bulbs with emery paper to clean and shine them up. Then check them again with your tester.

 

Your symptom is of a bad ground.

The tail lamp (stop/turn/running) circuit has a ground that goes all the way back to the cabin and is secured to the cab body behind the left kick panel.

At the trailer, make sure you are using a WIRED ground and that you are not relying on the trailer ball to try to get a ground.

 

i tried it with all four corner lights out and the blinker bulbs out. not only did I remove the bulb, but i removed the bulb socket from the wire harness as well. I'm thinking that rangers/explorers are all this way. I will try another ranger or explorer when I get a chance.

 

Lets think about this some more.

Did this probem come about suddenly, after some event????

For now, leave the tester out of the equation & concentrate on the trailer lights & the vehicles B+ 12 volt feed & ground connection soundness, at the trailer connector with the vehicles head lights on.

Make the B+ back probe test with a good DVM & with the trailer connector plugged in, so it's lamps are loading the circuit.

Look for excessive B+ voltage drop at the trailer connector, when the circuit is under load.
If B+ is low at the vehicles trailer connector, back up to where the trailer conector pigtail plugs into & splits off from the vehicles wiring harness for the tail lights. If B+ under load is ok there, the problem is somewhere in the trailer light pigtail harness, or it's wiring to the connectors pins/sockets.

If B+ checks ok at the trailer connector, check the B+ feed at the trailer lamp sockets for under load voltage drop between the connector & each tail light.

If the under load B+ feed to the trailer tail lights checks out, check the trailer ground connection at the connector & trailer chassis ground point/s for excessive voltage drop, caused by resistance from corroded/rusted connections.

You can make a quick ground test, using a good quality low resistance jumper cable, connected between a good clean metal connections on the trailer & vehicle chassis. This test parallels the trailers ground wiring, electrical connectors pins & sockets & both the vehicle & trailer ground points, to quickly determine if you have high reisitance somewhere in the ground path.

More thoughts for consideration, let us know what you find.

 

ok, I tried the tester on two more vehicles. one of them was another work truck which is a F-150 and I tried on a neighbors ranger. I got the same results as with my vehicle.

what started this whole things was, i hooked up to my trailer and noticed the left blinker on the trailer not working. I grabbed my tester and put it in the plug at the bumper and noticed it. I have since replaced a bad wire on the trailer that fixed the blinker.

to sum it up, this tester works differently on a 2010 f-150 than it does on a '97 ranger or '99 exploder

 

OK, good trouble shooting feedback & to hear you have it fixed.