We just purchased a 99 ranger 4.0l 4x4 with 26000 miles. The backup lights did not come on. I checked the bulbs, both were good, then checked the fuse it was blown, changed the fuse. both backup lights worked. drove to town and the backup lights did not work and the fuse was blown again. the owners manual lists the fuse also controls the electric shift, backup lamps, daytime running lamps, transmission control switch, and a pulse vacuum hub lock. any ideas were to start?

 

this one is going to be tough...
I'm not completely positive, but 99% this is caused by a short might be something completely different but its worth investigating... So, I would check for shorts in the wiring. i know easier said than done, but with aLOT, a whole LOT ofpatience this problem can be traced. Your at least somewhat mechanically inclined I'm guessing? You'll need a digital voltmeter/ohmmeter, if you don't have one you can usually pick one up for around 20 bucks. you'll be checking for continuity, that is electricity's ability to pass through an object. For example if you touched both wires on your tester to the negative post of your battery it would show continuity or conductivity, we'll refer to this as "cont" from now on. First disconnect your battery, no needto short other things too go to your fuse panel and pull the fuse that keeps blowing. touch one of your leads from the tester to the accesory post of that fuse slot and the other lead to a ground point. if it shows cont, you know for sure you have a short somewhere. then the only thing to do from there is go from system to system that fuse controls and try to isolate the short. undoubtedly if one accessory shorts it will also short the rest of the accessories on that circuit, so you will need to find some way to disconnect those from the rest. It will be painstaking and irritating, you'll want to burn the truck. literally. of course if this aint your gig, take it to a shop. it can get expensive real fast though, may be why they sold it, unless you got it from a dealer take that SOB back!!! make them fix it. I may have to publish this novel of mine. Hope this helps you out. if there's something you don't get let me know I'll see if i can't help some more. Good Luck!

 

Thanks for the information. I'll start there. I have a haynes manual and the wiring diagram is not very good. does anyone know whereI can get one on the internet, or another manual?

 

I think the last answer you got was very thorough, but I think I would put another fuse in it and with it running, shift through the gears, back and forth and see if the fuse blows again. That would pinpoint it to the trans range sensor, and I have seen them do that. Check the sensor for evidence of water entry, also check the connector for same. [sm=mail.gif]

 

Thanks! I changed the fuse, the backup lights worked, then i shiftedinto "D"and the fuse blew right away.Idisconnected the trans rangesensor switch and cleaned the contact switch now the fuse doesn't blow. Thanks again

 

I'm glad you got it fixed up the easy way. I wish I would of have thought of that. The most obvious answers are not always the right ones.

 

Glad it worked out for you. You might want to replace the sensor, just so you don't have future problems. [sm=mail.gif]

 

Thanks, I'll keep an eye on it and if it happens again I'll replace the sensor. Thanks for the help.

 

FYI; I have read, see or experienced several issues with moisture and connectors on our Rangers, IE passenger side air bag connector particularly sensitive on the super cab to high humdity. I was told to seperate the connector and fill it with dielectric grease. It sounds as if this may been called for with the range switch, as it will help keep out water the water 4wheelin helps put there.