Need Help Troubleshooting Various Electrical Bugs

[Anticitizen1]

Hey All, First post since signing up, longtime viewer of EF. I picked up a 1998 explorer and it has some various electrical issues. They are as follows, what I have tried to remedy these and other notes will be a separate list on the bottom.

• Instrument Cluster Lamps do not function. This is only the 6 bulbs that backlight the cluster, so all idiot lights appear as they should. Also, the interior cabin lights and HVAC controls work. I have replaced all bulbs with brand new ones, no Bueno.
• The blend door knob to adjust temperature (NO EATC, this is an XLT) will only actuate the blend door with the HEADLIGHTS OFF. Blend door has been verified to work with no issue when the headlights are off. The blower speed and knob to adjust the air direction work regardless of the headlights being on or off, and the backlight for this control DOES WORK. I believe it may be correlated to the instrument cluster issue.
• The fog lamps do not illuminate nor does the backlight on the switch, and same for the rear defogger switch. I have not attempted diagnosing these issues yet, they may or may not be correlated to the above two issues.
• The Hi-Beam indicator on the instrument cluster (blue lamp icon) is illuminated when the LO-Beams are on. Flip on the Hi-Beams on the turn signal stalk, and the light goes out. ALL headlights/taillights work as they should otherwise besides the fog lamps as above mentioned.

The previous owner had an aftermarket sony stereo wired in, and it was a bit of a hackjob with several bare connections. I cut back the harness and found an exact match at the junkyard, along with the 1998 xlt correct factory stereo and spliced it back in. I have one extra wire in the radio's connector, I believe a light blue with red tracer, that has no match in the factory harness. All other wires matched up with my trucks harness, and the radio work perfectly as it should. The other things I have tried are as follows:

• I CHECKED ALL FUSES FIRST WITH MULTIMETER
• I replaced all bulbs in the instrument cluster.
• I checked power to wire 235 (red with black tracer) in the instrument cluster, appears to function properly with switched 12v power from headlight switch.
• I checked major/minor grounds for continuity, all appear to be grounding well with good continuity.
• I replaced headlight/dimmer switch with a few junkyard replacements each, to no avail.
• Checked and rechecked all connections for frays, breaks, melt points, including the Ford approved "Wiggle Test" haha.

I believe that is all the information off the top of my head. I really appreciate any and all help I can get on this issue. If anyone has any questions, please let me know and I will do my best to answer quickly. Also, I hae the 1998 factory service manual set for my truck in case anybody needs me to look at a diagram. THANKS!

 

[koda2000]

About the only thing involved you haven't checked/replaced is the multi-function switch. IDK if this is your issue, but it's involved with some of the issues you're having (high beam indicator, fog lights). Be sure to check the wires where they plug into the MF switch, they sometimes pull loose because the harness is too tight and pulls when the tilt wheel is used. It's not uncommon for the back-light bulbs in the switches (headlight, fog light, wipers, cruise controls) to burn out, especially the headlight switch. None of this explains your dash illumination lights or blend door issues, but who knows how the wiring may be related w/out checking wiring diagrams.

 

[Anticitizen1]

When you say the multifunction switch, are you referring to the stalk on the left hand side of the steering column that controls the high/lo beams, turn signal and windshield washer? I have not tried that as a matter of fact, very good point. I'll try that next, you very well may be right on the tilt column damaging connections.

 

[koda2000]

When you say the multifunction switch, are you referring to the stalk on the left hand side of the steering column that controls the high/lo beams, turn signal and windshield washer? I have not tried that as a matter of fact, very good point. I'll try that next, you very well may be right on the tilt column daging connections.

Yes.

 

[Spitfire1966]

Have you checked the auxillary relay box under the mass air flow sensor just to the right of the air box and a little bit back( 8") from the air box? It is a black box about 2" wide by 4" long. Open it and Pull out the relays, mark them with tape, and exchange them with the main relays by the battery. You can look for images of relay boxes online and you will see the box and it does operate your front window washer squirter and I am pretty sure it operates the rest of the stuff that is not functioning in your truck. The blue wire left over from your radio install is probably for an aftermarket amp for a speaker. Tape it up.

 

[Anticitizen1]

SOLVED!!!
My instrument cluster's illumination circuit didn't have proper grounding, go figure. I had already tested for ground continuity and 12v power, and found both at the cluster. Tore my hair out trying to solve it, and finally decided to just splice in two jumper wires from the headlamp switch just because I know that will only energize the circuit when the switch is on. So I did so, LO AND BEHOLD! Then my turn signals didn't work. Backtracked and disconnected my splices, still no turn signals. Searched the forum and learned of the infamous tilt column wiring issue. Fixed the turn signals by lifting the column up, and connected the ground splice first and that fixed it by itself! I think I was backfeeding ground continuity to the point I thought it was there, but it wasn't GOOD ENOUGH. Here's the kicker, this also FIXED the blend door issue, AND the rear defogger issue, AND the High Beam issue. Grounds are weird...

Thanks everyone for all your help, VERY much appreciated.