How do turn signals work?

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#Get your DVOM out, set it for volts scale, V X 50 or higher, and turn the key on then the offending signal.
 
#Get your DVOM out, set it for volts scale, V X 50 or higher, and turn the key on then the offending signal.
 
#Carefully insert the probe of your meter into the socket, to the contact pad (S) on the bottom of the socket, and the other to a good ground.
 
#Carefully insert the probe of your meter into the socket, to the contact pad (S) on the bottom of the socket, and the other to a good ground.
#If you read 0, then 12 volts then zero (flash signal), the power to the lamps and the system are working fine. You have a bonding issue.
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#If you read 0, then 12 volts then 0 again (flash signal), the power to the lamps and the system are working fine. You have a bonding issue.
 
#Shut off power to the system, and key, and return to the offending socket.  
 
#Shut off power to the system, and key, and return to the offending socket.  
  
New Cars today have Plastic Bumper’s and Anti Collision Systems. Proper Ground Bonding is becoming Scarce Compared to Bygone Days...and Lighting systems have had to relay on "Wired" or "Remote Location" Grounds. It is quite common to lose ground to a single socket and disable it.
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New cars today have plastic bumpers and anti-collision systems. Proper ground bonding is becoming scarce compared to bygone days. Also, lighting systems have had to rely on wired or remote location grounds. It is quite common to lose ground to a single socket and disable it.
  
Set your Meter for OHMS Scale, R X 1, Calibrated 000, and measure between the socket and a KNOWN good ground. Your reading here must be 000, if infinite, or random, you need to perform good bonding repairs to the socket...
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Set your meter for OHMS Scale, R X 1, calibrated 000, and measure between the socket and a known good ground. Your reading here must be 000, if infinite, or random, you need to perform good bonding repairs to the socket.
  
Using a Good Contact cleaner, carefully CLEAN the socket, Pads and lamp Brass base and its pads. Next recheck the socket for bonding, if your readings are still infinite or random, replace the ground wire to a known good ground area. Use a star washer and burnish all the paint and dirt from the bonding area.
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Using a good contact cleaner, carefully clean the socket, pads and lamp brass base and its pads. Next, recheck the socket for bonding, if your readings are still infinite or random, replace the ground wire to a known good ground area. Use a star washer and burnish all the paint and dirt from the bonding area.
  
That will get a Single lamp back to operation.
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That will get a single lamp back to operation.
  
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SYSTEM DEAD:
 
  
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===Dead system===
  
If none of the turn signal functions work AT ALL...
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If none of the turn signal functions work at all, follow the steps below.
  
The first stop is the fuse. pull it and with your DVOM, measure it on OHMS Scale, R X 1 , Calibrated 000, If it reads infinite, it is open Replace the fuse and test the signal system again. If it reads 000, it is good, put it back in the buss box.
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#Pull the fuse, and with your DVOM, measure it on ohms scale, R X 1 , calibrated 000.
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#If it reads infinite, it is open. Replace the fuse and test the signal system again. If it reads 000, it is good, put it back in the buss box.
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#Next, set your meter to DCV, V X 50 or auto range, turn the key on, and remove the flasher. Place the black probe on ground, the the other into either of the two flasher terminals. One will read infinite, the other should read 12 volts. If you have that, power is good to the flash unit.
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#Next, set your meter to ohms, RX1 scale and measure across the flasher. It should read 000. If it does not, it is open, replace the flasher. If it does read 000, it is good (at least for one flash). If that is what happens, replace it with a known good or new one.
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#Next, Replace the flasher. Turn either signal on, turn on the key, and isolate the wire from the flasher to the steering column plug. Measure it with your DVOM set for DCV, V X 50 or auto range, and ground. It should read an intermittent 12 volts, or a steady 12 volts if nothing in the system is working. If you have neither, check the wire between the flasher and the column plug for cut condition, or a burned socket.
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#If you have either a cut condition, or a burned socket, check the other side of the column plug. It should read the same as the first reading. If you don't have that, pull the plug, inspect the pins for clean mating surfaces, and burned or bent pins or wires. Repair or replace as required.
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#If you don't have either a cut condition, or a burned socket, and still dead, check any lead front, or rear of the selected side. It should have 12 volts, either steady or intermittent on it. If not, your trouble is in the column harness between the plug and the switch. Or, the switch itself is bad. Repair or replace as required.
  
Next set your meter to DCV, V X 50 or auto range, Turn the Key On and remove the flasher. Place the black probe on ground, the other into either of the two flasher terminals, One will read infinite, the other should read 12 volts. If you have that, power is good to the flash unit.
 
 
Next, set your meter to OHMS, RX1 scale and measure across the flasher, it should read 000, if it does not, it is open, replace the flasher. If it does read 000, it is good (at least for one flash) if that is what happens, Replace it with a known good or new one.
 
 
NEXT, Replace the flasher, Turn either signal on, turn on the key, and isolate the wire from the flasher to the steering column PLUG. Measure it, With your DVOM set for DCV, V X 50 or auto range, and ground, It should read an intermittent 12 volts OR a steady 12 volts if nothing in the system is working. If you have neither, check the wire between the flasher and the column plug for cut condition, or a burned socket. If you have either:
 
 
Check the Other side of the column plug. It should read the same as the first reading. If you don't have that, pull the plug, inspect the pins for clean mating surfaces, and burned or bent pins or wires. Repair or replace as required.
 
 
If not, and still dead, check any lead front, or rear of the selected side. It should have 12 volts, either steady or intermittent on it. If not, your trouble is in the column harness between the plug and the switch. OR the switch itself is bad. Repair or replace as required.
 
 
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FRONT SIGNALS WORK BUT REAR IS DEAD:
 
Or Visa Versa:
 
  
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===Front signals work, but rear signals are dead (or vice-versa)===
 
Isolate the two wires the effected end, from the column plug. Using your voltmeter set to the above parameters, selects a side and measures the wire from the plug. It should show 12 volts (solid or intermittent), If not, you have a switch / harness failure. Inspect, and repair or replace as required.
 
Isolate the two wires the effected end, from the column plug. Using your voltmeter set to the above parameters, selects a side and measures the wire from the plug. It should show 12 volts (solid or intermittent), If not, you have a switch / harness failure. Inspect, and repair or replace as required.
  

Revision as of 10:55, 11 September 2006

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