I don't have Tail Lights (Red) nor front running lights (Amber), Instrument Panel lights, including the dimmer switch, and liscense plate and back-up lights. However, I do have Brake Lights, Turn Signals, Headlights, Interior Lights (Dome Front and Back and Both Door Lights. I checked the fuse panel inside the driver's door and found a 15 Amp fuse that says: Tail, Illumination light. I took the fuse out and checked it on a meter and it was good. However, I changed out the old fuse with a new 15 Amp. This made no difference at all. Still missing Tail, Instrument Panel, Back-up, front running lights and liscense plate lights. Other than that 15 Amp fuse, what else is common with all of those lights? It might be right in front of my face, but I just don't see it.

STOP and PARK LPS will be tail lights.

ILLUM and GAUGES will.be dash lights.



STOP
Stop/CHMSL, Stoplamps

GAUGES
IP Cluster, DRL Relay, DRL Module, HDLP Switch, Keyless Entry Illumination, Low Coolant Module, CHIME Module, DRAB Module

PARK LPS
License Plate Lamp, Parking Lamps, Taillamps, Front Sidemarkers, Glove Box Ashtray

ILLUM
LP Cluster, HVAC Controls, RR HVAC Controls, IP Switches, Radio Illumination, Door Switch Illumination

The tail lights work off the headlight switch, and there is a fuse for the tail lights. Make sure the fuse is good, first, a 15 amp (blue) fuse in the instrument panel fuse block. Then, you might have a bad headlight switch.
So you DO have dash lights, they just don't dim from the dimmer switch? In the wiring diagram, there is a green wire from a "tail light relay" (in the "Junction Block-Right Instrument Panel") that carries power to all the exterior lamps, as well as having a splice to the Instrument Panel Cluster (illum. bulbs), and to the lamp dimmer, and to the radio bulb.
To do any further testing, you would need a voltmeter or a test light, so you could chase down this power loss. Good luck.

Park lamp fuse 20amp located in the under hood fuse box .DRL control module
Daytime Running Lamps (DRL) Control Module
Right of the steering column, behind the IP
Park, Sidemarker, Tail and License Lamps
Voltage is applied continuously to the PARK fuse to the headlamp and the instrument panel (IP) lamp dimmer switch through CKT 1340.
When the headlamp and the (IP) lamp dimmer switch is in the PARK or HEAD position, voltage is applied to CKT 9 thus activating the following lamps:
• The park lamps
• The side marker lamps
• The tail lamps
• The license lamps
The park/turn lamps are the only lamps that do not activate yet receive a current from CKT 9. The park/turn lamps do not activate because the voltage drop across the front side marker lamps is much higher than that across the turn lamp filaments Step
Action
Normal Result(s)
Abnormal Result(s)*

1
Turn the headlamp/instrument panel (IP) lamp dimmer switch to the PARK position.
The following lamps light:
• The license plate lamps
• The taillight lamps
• The front side marker lamps (Domestic)
• The front parking lamps (Domestic)
The headlamp position lamps (Export)
Refer to Park Lamps Inoperative
Park Lamps Inoperative
Step
Action
Value(s)
Yes
No

1
Inspect the PARK LP fuse.
Is the fuse open?
--
YES - Go to Step 2
NO - Go to Step 3

2
Repair a short to ground in CKT 1340.
Is the repair complete?
--
Go to Exterior Lights System Check
--

3
Turn the headlamp/instrument panel (IP) lamp dimmer switch to the PARK position.
Use a test light in order to backprobe the headlamp/IP lamp dimmer switch harness connector between terminal R and ground.
Did the test lamp light?
--
Go to Step 7
Go to Step 4

4
Use a test light in order to backprobe the headlamp/IP lamp dimmer switch harness connector between terminal O and ground.
Did the test lamp light?
--
Go to Step 5
Go to Step 6

5
Replace the headlamp/IP lamp dimmer switch. Refer to Headlamp Switch Replacement .
Is the repair complete?
--
Go to Exterior Lights System Check
--

6
Repair the following conditions in CKT 1340 between the PARK LP fuse and the headlamp and the IP lamp dimmer switch harness connector terminal O:
• A faulty connection
• An open circuit
Is the repair complete?
--
Go to Exterior Lights System Check
--

7
Repair the following conditions in CKT 9 between the headlamp and the IP lamp dimmer switch harness connector terminal R and S204:
• A faulty connection
• An open circuit
Is the repair complete?
--
Go to Exterior Lights System Check

that line on that fuse is shorted, the fuse saved the fire.
we use an ampclamp DC ammeter to find the wire that is shorted
and the actual point of short.

the park-tail circuit (tail fuse, right) is the most complex of all.
20 lamps inside car, and many out side, it is the hardest to find of all shorts. but not with the tool
first check for damage behind all park lamps
i bet the fuse blows in park (1st click) not head lights. right?
side lamps the 4 front rear park lamps, some call it tail its not really tail now, was in 1920 ,not now. park is everywhere.
but the fuses can be marked tails, for fun .
imagine, calling the 2 front lamps tails. and are on .(my on going joke)
sidelamps,
the inside lamps are many too.
all dimmable lamps. so turn the dimmer down to zero and see if fuse blows now, NO?, bingo.

the best way to fix this is , visual inspections for collision damage or wire hacks in the cab.
then the fuse is pulled and circuit breaker inserted 15amp
(they sell em)
then we connent the ammeter to the wire (output of fues)
i push the switch and amps goes to infinity and the CB trips
if follow the cables, and find what line is shorted.

i missed one problem
on the rear or front 4 corners of the car may be twist lock blubs.
like 1157 or? these love to short. push in lamps never short.well not the lamp actual.
in not sure what lamps the 06 uses, but replace the brass based lamps. (in park tail ckt)

No. Dash lights being out could be a bad headlight switch, since the dash lights are routed through the headlight switch, not the dimmer switch. Park and tail lights also controlled by the headlight switch.

The tail and marker lights and Instrument lights are on the same circuit so both will go out if the fuse for this circuit blows. If fuse continues to fail, check the tail light or marker globes, including the globes for the number plate, for a globe that may have an internal short causing the fault and replace as necessary. As you have already checked the wiring near the light fittings for any chafed wires that could be shorting to the body causing the fault, then a closer inspection of the wires inside all the light assemblies for any shorts may be needed.

It could also be that the instrument dimmer control has failed and is causing the fault. The electronic bits inside the dimmer control for these lights sometimes go faulty. Try disconnecting the connecting plug on the rear of the dimmer control and checking if fuse still blows. If fuse continues to fail, then the fault in the tail and marker lights circuit.

Remove all the tail, number plate and running light globes from the light assemblies and leave the instrument dimmer control disconnected and check if fuse still blows.

Disconnect the plug near each of the light assemblies to see if any of the individual assemblies is causing the fault. With all light assemblies disconnected and fuse continues to fail, then the fault must be in the main wiring loom some where.

If you have a Multimeter, it could be used to determine which light assembly has a fault between the lamp supply and earth connection.

The tail lights and licence lamp is all the same circuit, should be a brown wire to all 3, it sounds like its broken in the harness somewhere (especially if the front park lamps work, then the fuse and switch are good). Trace back from rear lights until you find power. Check for pinched wires or cut, or bulges in the wire indicating resistence. Also if you have wired in a trailer plug, disconnect it and retry. Trailer wires are very seldomly wired properly and cause lots of light issues.

1st check the fuses-----then the globes-----check all the fuses some have multiple tasks if you have a test light ,youcan test to see if thre is power on one or both sidesof the fuses with the lightswitch on.if thre is no power there the swich is the next place to checkfor power to those items not working. i cant remember if there is a relay on those ,but look for one

I can give you 94 mustang. Don't have 86 but maybe similar

Pin Number Circuit Circuit Function B1 38 (BK/O) Power Supply to Battery B2 195 (T/W) Tail Lamp Switch Feed I 19 (LB/R) Instrument Panel Lamp Feed IGN — Not Used R 14 (BR) Headlamp Switch to Tail Lamp and Side Marker Lamps H 15 (R/Y) Headlamp Dimmer Switch Feed DN — Not Used D1 54 (LG/Y) Interior Lamp Switch Feed D2 706 (GY) Battery Saver Door Switch Feed