dickandlois Report post Posted May 25, 2018 Do you have a multi meter? set it at ohms, The Greek symbol for omega. With the power off to all the lighting circuits, read the resistance of the ground wire to the chassis ! you might want to make up a ground long ground wire with a clip large enough to connect to a good point on the chassis. If your meter has a zeroing feature - short the 2 meter wires together at the ends used to measure the circuits. Set to meter to zero. THEN measure the resistance of the jumper wire you made up. You can then reset the zero point on the meter wit the jumper wire connected, re zero meter or just wright down the number. Now you measure the ground wire from each lamp and wright down the numbers. They will be from 0 to infinity. the closer to zero / the better the ground point, The higher the number the farther the connection is from ground. Measuring something like 0.005 has a better connection then one that reads .09 or greater like 1000 or 10, 10,000. Numbers like that will indicate bad grounds. Even 15, 20 or higher have connection issues that need to be address. link to learn- https://learn.sparkfun.com/tutorials/how-to-use-a-multimeter/all.pdf Rich. Share this post Link to post Share on other sites
dickandlois Report post Posted May 25, 2018 4 minutes ago, jleamont said: Edain, so you put a single pole bulb into a double pole outlet? What was the bulb number 1156/1157 style or 3156/3157? I'm trying to picture if you shorted to GND or other light circuit. Rich, was Freightliner Module happy in 1999 or did they jump in with that stuff later on? Does it do it with Hazards on also? If you are sure the grounds are clean I wonder if it back fed into the turn signal switch and damaged it. Most often everything passes through that switch, some have a small circuit board built in and diodes. I'm not familiar with that switch design in 99 on a Freightliner chassis. Joe,the simple answer is YES, because LED lights require only mil amps to light, and any path to power will allow them to light - Even if dimly and will off ten cause other issue in the lighting circuits. Rich. Share this post Link to post Share on other sites
edain08 Report post Posted May 25, 2018 yes 1156 into 1157 replaced both flashers turn and 4 way Hazards appear normal except when headlights are on - then no flash - both before and after replacement of 4 way Bulbs I have replaced: Headlights Right turn signal 194 right side 1157 both sides 1157 trim bulbs both sides replaced 194 socket right side replaced 1157 socket right side replaced combiner ran grounds for right side Share this post Link to post Share on other sites
edain08 Report post Posted May 25, 2018 also checked rear turn signal bulbs on right side for crossed filaments - nothing found All bulbs function Share this post Link to post Share on other sites
dickandlois Report post Posted May 25, 2018 12 minutes ago, edain08 said: also checked rear turn signal bulbs on right side for crossed filaments - nothing found All bulbs function Do you have the chassis wring diagrams you you coach. There could be an issue(s) with the turn signal switch mounted under the steering wheel and that might be more then you want to venture into. You could run a circuit test at the connector between the switch and the connector under the dash that connects it to the main chassis harness. Look at the link to tutorial link I attach if you need some refresher info in a post just up from here in a reply! Rich. Share this post Link to post Share on other sites
edain08 Report post Posted May 25, 2018 Here is what I got from Freightliner ZWiring schematicsD06-28749.pdf Share this post Link to post Share on other sites
dickandlois Report post Posted May 25, 2018 20 hours ago, edain08 said: Here is what I got from Freightliner ZWiring schematicsD06-28749.pdf GOOD ! Look in the lower left hand corner with the drawing blown up and you will see the wiring diagram for the turn signal switch> measure from pins to pins to any shorts that show up - when the switch is open on both Left and Right or any shorts between any pin to pin that the drawing shows as open !!!! My bad, look at page 1 in the upper left hand corner. Hasty makes Wasty Rich. Back in the sticks and bricks ! Share this post Link to post Share on other sites
