Troubleshooting Turn Signals

From: Ray Fichthorn
via the Studebaker Newsgroup

Problem:  Front and rear lights are working although turn-signals and stop lights do 
 not....

The brake lights and dome light are on the same circuit- If neither work, this may 
indicate a problem with the fuse. Check (them) first. The "lower" fuse on the panel 
is for the brakes.. the "upper" fuse is for the directional signals. While you are 
"poking" around there- unplug the flasher unit- and clean the terminals. Then test
 all the bulbs in the circuit.

The parking lights do not work either.

The headlights and (front) park lights are on different circuits- the front "park" 
lights only come on when the dash switch is in the down position (no headlights). 
This position is seldom used, so internal corrosion is likely. I usually can jiggle 
and play with the switch to work the corrosion off.. Try that with someone out front
 looking for the park lights to flash or come on. If they do, but won't stay on, you
 may need to disassemble the headlight switch to clean it- as that is where the problem is

When I pull the turn-signal lever up or down nothing at all happens. Should the
 directional lights the instrument panel flash like a modern car?

Yes, the indicators in the dash flash when the turn signals are in use. You should be
 able to hear the flasher unit clicking. If one of the indicator lights comes on 
(and stays on)- AND you hear the flasher "clicks"- but the indicator bulb doesn't
 flash- That usually indicates a burnt-out turn signal bulb on that side.

And what would I do with the stop lights?

As stated before- check the fuse and the bulbs first. Then proceed to the Brake Light 
Switch. It is located on the frame- to the left of the engine (drivers side), below 
the starter solenoid, in front of the steering box..just behind the upper control arm..

get the idea? It's a round sender with 2 "posts" sticking up from it. Unplug the 2 
wires from it (it doesn't matter which goes where). One is RED, the other is RED 
with a WHITE tracer. 
The RED one should be "hot". Use a test light to verify you have power... ..or you 
can use a jumper wire to bypass the brake light switch. If the brake lights work, the switch is either bad or the terminals/connectors are corroded.

This is the point that the Turn Signals get complicated. When you are STOPPED with 
your foot on the brakes (both brake lights on).. and turn on the turn signals- The
 corresponding BRAKE light bulb must be bypassed- so that the filament will flash.
 This is where the 2 circuits are dependant on each other. The RED/Wt tracer wire 
from the brake light switch- goes into the main harness up to the Turn Signal Switch 
(TSS). The TSS.. breaks the circuit to that brake light- when the Directional Signals
 are used. IF the TSS is corroded (common) or burnt out (not so common)... the 
directional signals will not work. You need to check for power at the TSS Connector 
(about 1" square black junction block)- where it comes out of the steering column and
 into the Main Wiring Harness. Here's what to look for:

   1. ***Turn ignition switch to the Accessory position***
      Check for power to the TSS at the BLACK Wire going TO the connector from the
 main harness The lead should be "hot"
   2. Place the lever in the Left Turn position, and check for power on the TAN 
wire and the White w/TAN Tracer wire going TO the connector FROM the TSS. Both 
should be "hot".
   3. Place the lever in the Right Turn position, and check for power on the
 GREEN wire and White w/GREEN Tracer wire going TO the connector FROM the TSS.
 Both should be "hot".
It's important that these wires be returned to their original positions... So 
try to do them 1 at a time. It is also wise to use some small needle-nosed pliers 
to unplug the the wires from the junction block. Usually a small twist will
 release them.
Somewhere you will find something amiss... hopefully it's just corrosion, 
fuses, or bulbs. Long-distance electrical troubleshooting is difficult! <BG>

Ray