My fiance's 03 WJ has no working turn signals. We replaced the flasher relay and still nothing. Could it be the turn signal switch? The rest of the controls on it work. Any suggestions on what else I can test and replace?

 

May want to check the brake light assembly,mine had a bad connection there where the bulb connects,and only works sometimes when I especially hit a bump,it then seems to get connection and works for a bit,if it sets and the assembly cools off it will stop working again....hope this helps

 

First check the fuses (fuse #4 & #20 in the junction block under the hood). Verify continuity at these two fuses with the ignition key turned off.

From the manual:

1) Turn the ignition switch to the Off position. Check the ignition run fuse (Fuse 20 - 10 ampere) and the flasher fuse (Fuse 4 - 15 ampere) in the Junction Block (JB). If OK, go to Step 2. If not OK, repair the shorted circuit or component as required and replace the faulty fuse(s).

(2) Check for battery voltage at the flasher fuse (Fuse 4 - 15 ampere) in the JB. If OK, go to Step 3. If not OK, repair the open fused B(+) circuit between the JB and the Power Distribution Center (PDC) as required.

(3) Turn the ignition switch to the On position. Check for battery voltage at the ignition run fuse (Fuse 20 - 10 ampere) in the JB.

These are probably some of the first steps you should take checking the fuses, and for having the proper power getting to them.

If needed, you can test the flasher relay to see if it has power to it as described from out of the factory service manual:

(1) Turn the ignition switch to the On position. Check for battery voltage at the fused ignition switch output (run) circuit cavity in the JB receptacle for the combination flasher. If OK, go to Step 2. If not OK, repair the open fused ignition switch output (run) circuit between the combination flasher and the ignition run fuse (Fuse 20 - 10 ampere) in the JB as required.

(2) Turn the ignition switch to the Off position. Check for battery voltage at the fused B(+) circuit cavity of the JB receptacle for the combination flasher. If not OK, repair the open fused B(+) circuit between the combination flasher and the flasher fuse (Fuse 4 - 15 ampere) in the JB as required.

From there.. if needed, you can begin testing of the multifunction switch:

(1) Disconnect and isolate the battery negative cable. Disconnect the instrument panel wire harness connector for the turn signal and hazard warning switches from the left (lighting) multi-function switch connector receptacle. Check for continuity between the ground circuit cavity of the instrument panel wire harness connector for the left multi-function switch and a good ground. There should be continuity. If OK, go to Step 2. If not OK, repair the open ground circuit to ground (G200) as required.

(2) Check for continuity between the hazard switch sense circuit cavity of the instrument panel wire harness connector for the left multi-function switch and a good ground. There should be no continuity. If OK, go to Step 3. If not OK, repair the shorted hazard switch sense circuit between the left multi-function switch and the combination flasher as required.

(3) Check for continuity between the hazard switch sense circuit cavities of the JB receptacle for the combination flasher and the instrument panel wire harness connector for the left multi-function switch. There should be continuity. If OK, go to Step 4. If not OK, repair the open hazard switch sense circuit between the left multi-function switch and the combination flasher as required.

4) Check for continuity between the left turn switch sense circuit cavity of the instrument panel wire harness connector for the left multi-function switch and a good ground. There should be no continuity. If OK, go to Step 5. If not OK, repair the shorted left turn switch sense circuit between the left multi-function switch and the combination flasher as required.

(5) Check for continuity between the left turn switch sense circuit cavities of the JB receptacle for the combination flasher and the instrument panel wire harness connector for the left multi-function switch. There should be continuity. If OK, go to Step 6. If not OK, repair the open left turn switch sense circuit between the left multi-function switch and the combination flasher as required.

(6) Check for continuity between the right turn switch sense circuit cavity of the instrument panel wire harness connector for the left multi-function switch and a good ground. There should be no continuity. If OK, go to Step 7. If not OK, repair the shorted right turn switch sense circuit between the left multi-function switch and the combination flasher as required.

(7) Check for continuity between the right turn switch sense circuit cavities of the JB receptacle for the combination flasher and the instrument panel wire harness connector for the left multi-function switch. There should be continuity. If OK, test the left multi-function switch. (Refer to 8 - ELECTRICAL/ LAMPS/LIGHTING - EXTERIOR/LEFT MULTIFUNCTION SWITCH - DIAGNOSIS AND TESTING). If not OK, repair the open right turn switch sense circuit between the left multi-function switch and the combination flasher as required.

I would start at the fuses and make sure there is power getting to them, and then trace it until you find out where it stops.

You could turn on your emergency flashers while simultaneously checking for an on/off of a 12 VOLT read with a multimeter at the lights assemblies too, as this could indicate as having a bad ground (and let you know the power is making it there).

 

You can go to a site like this and review the factory service manual (FSM) online. It can easily be downloaded too. In case you may need wiring diagrams etc...