Ive been going nuts trying to get my "87 Bronco dad gave me road worthy again. My instrument cluster lights stopped working, ok. The light blue/red wire from the headlight harness should be for the cluster illumination when the headlight switch is pulled. Im getting no current form the accesory wire to the light blue/red wire through the assembly. I thought it was just a bad switch so I get another one from the junkyard, that one is the same way. Is this a common problem in the rangers and broncos? Should I get another switch and try it again? I started to bypass with a toggle switch but I then lost my brakelights. Im tired of messing with this after over a week. Appreciate any responses.

 

It sounds like you may have a problem similar to one I had!

I suggest first checking the 5-Amp fuse for the Instruments. If it's fried, replace it. Then, in low-light conditions, turn the light **** clockwise about 1/4 to 1/2 way before turning on the Parking lights to see if your instruments illuminate at all.

If there's no illumination, start looking for a short-to-ground anywhere on any light-blue/red wire you find. If you have an automatic transmission, look under the shifter floor cover (console). Four screws hold it onto the floor plate. A light-blue/red wire (together with a black ground wire) feeds power to the shifter console lamp. The light-blue/red wire can get pinched and shorted to ground, shunting all the power from your instrument lights.

Also, if you have the electronic shift transfer case, the same wiring feeding power to the light in the 4x4 overhead console could be shorted.

Look first around areas where work was recently done. For instance, if the automatic transmission was serviced, someone may have had to lift or remove the floor console to do the job and when it was reinstalled, that lamp wire may have gotten pinched against some sharp metallic object. Or if the radio was serviced or upgraded, maybe the light-blue/red wire was not correctly connected or insulated if not used.

Hope that helps

 

Yeah I lloked at the fuse, it was fine. I'll look more for a grounded wire. Its a standard shift. It seems if it was just a grounded wire that a fuse would be tripped(fried) when another accessory from the fusebox was hooked up to it. I'll try searching again tonight. Thanks for your reply HO4wd

 

Incidently, I had the same problem with my '88 - no instrument lights. I first checked the fuse and found it to be OK as well. The only thing that happened between when the instrument lights worked and when they didn't was me removing the automatic trans floor shifter console to clean the carpet in the area. Apparently, when I reinstalled it, the light-blue/red wire literally got screwed, thus shunting the power to ground there.

I agree one would expect a fuse to blow when a short occurs. But, bear in mind, that fuses can't always be relied on as troubleshooters. Their purpose is to prevent WIRING overloads and their resulting catastrophies. In this case, I expect the dimmer control provides enough resistance to keep the fuse from blowing. The instrument lamps are rated at 12 volts, though they will glow with voltage as low as 5 or 6. A shunt can drop the voltage to 2 or 3 volts; too low to illuminate the bulbs and with the dimmer in series, still may not open the fuse.

That fuse feeds power to ALL the panel lamps: Instruments, A/C-Heater-Vent control panel, Radio, Glovebox lamp (if equipped), Ashtray (if equipped) and any auxilliary factory control switches, such as Rear-window Wiper/Defroster, etc. If the failure is confined to JUST the instrument cluster, go straight to the electrical connection at the back of the cluster.

If ALL panel lamps fail to illuminate, not just the instrument cluster, then continue with your troubleshooting. By the way, some of those low-amperage fuses can open without readily showing it to the unaided eye. Try a good spare 5-amp fuse, if you have a few extras to waste, and see if the lamps work then. If replacing the fuse doesn't fix it, the problem elsewhere.

At this point, a multimeter than can measure up to 10 amps, would be very useful. Pull the "Instrument Lamps" fuse, set up the meter for 'DC Amps' and connect its lead probes to the fuse receptacle connections.

If the meter is the analog type, watch for movement when you turn the parking lights on; you might have to reverse the leads if the polarity is wrong. Most digital multimeters will work regardless of polarity, showing either positive or negative current flow in its display.

--> If the current flowing through the fuse connections gets close to 5 amps, you've got a shunt somewhere. The fuse may also need to be replaced.

--> If it's around 1 or 2 amps, see if the panel lamps are now working. If they are, replace the fuse.

--> If you have NO current flowing, there's an break somewhere in the wiring. Set up your meter to check for 12 VOLTS, then start at the fuse receptacle connections and work your way out toward the panel lamps.

Have patience and perserverence, you WILL eventually find the problem!

 

Finally I went and bought a new headlight switch after trying 2 from the junkyard with no success. It works again. All that tearing apart everything for just about nothing. I did get a chance
to install some ne 5.25 pioneers in the dash though. After I get the 12's inIll be shaking the rust off. haahaha