Thread: The wiper headlight dilemma with indicators

Well my ride has finally circum to the dreaded wiper turns on when the head lights are on problem.

I am looking to find a solution on how to solve this. I have tried an internet search but could not find an answer other than to check you plugs and switches. Not relevant in this situation and I am way beyond that fault finding area hence the ask for help.

So, problem is wipers operate fine on their own. Headlights operate fine at first with the added bonus of the wipers start up at the same time after additional testing. Also in the mix the hazard lights or indicators no longer work. I hear the relay but no lights.

Backstory.
All was working fine before for years.
Took out the rear wiper switch, removed the cigarette lighter and stereo. Replaced the dash and binicle with a metal one. Plugged in the rear fog light relay module. Tested the headlights and fog light. All worked. Continued with replacing the illumination lamps. Put all dials and warning module back in and tested.

Testing.
tried the hazards first. Not working.
tried the indicators next. Not working.
tried the side lights. Worked.
tried the head lights. Worked.
tried the rear fog light. Worked.
tried the self reset with fog light and head lights. Worked.
tried the diff lock light. Worked.
I think it was now that I replaced the lamps. Replaced the five dash illumination lamps with led’s. Replaced the diff lock and indicator lamps with 2.3w bulbs.
Looked at other dash warning lights. Worked.

Located the dash in position and tried testing again.
Got to the head lights test again and this time the wipers started. Found I had nocked the wiper stork when putting dash in place. Turned off the wipers and started testing again.

Testing again gave the same results of the wipers operating when the head lights are on.
Removed the fog light module and tried again, but still the same, so plugged the fog light module back in.

I have not touched either the wiper switch or head light switch whilst carrying out any works this time. Both wiper and head light storks are new and was replaced over a year ago with decent Lucas branded ones. All worked prior to this current work.

With my fault finding I have eliminated the fog light module as this has no effect with it in or out. Checked all wiring was put back as original. (Photos taken before for reference).

So the only thing that I haven’t put back as it was before is to put back the filament lamps.
Could this really affect this?

So if any of you have had the same and found a solution I would be glad to hear from you. Also if anyone has any suggestions of other things to try, I would welcome that.

Additional.
There has been some electrical work in the past with previous owners that has been carried out behind the dash and cigarette lighter, but none of this was touched or altered and has been working fine. Last item to note the rear wash wipe switch and cigarette lighter are not connected still.


ps. My vehicle is a 1998 300 TDI (110)

Additional info. Testing in the dark
The simple action of fixing the dash in place has now made the lights and wiper situation resolve its self. This action leads me to believe there was a neutral missing and a back feed was introduced since there was no path for current to flow. So now that the dash is in the correct location a neutral must now be using the metal binicle and dash to make the return path. I can look into this further if I encounter this again but for now I will move on.

I now only have to resolve the hazard lights / indicator not working. Will start the testing again tomorrow starting with the connector at the rear of the switch as this is the only place that may have been disturbed whilst getting the dash wiring plugged in. I will keep you all updated.

Day two
Two steps forward and one back.
Well I fixed my hazard / indicator problem. I had one of the small side wires on the hazard switch disconnected (must of got pulled out when working on the dash). But the main issue was my electronic relay was dead. My relay was already dying as I have had intermittent issues before but this time it was kaput. Changed it out for a new one and my hazard / indicators all work fine now.

I had to remove the dash again to connect the speedo cable and whilst it was off I decided to relocate my wiring for my brake controller. It was installed with haste when I collected a new trailer a couple of years ago. So now all wiring was fully concealed behind the dash. Also I re-routed the speaker wiring that a previous owner had installed. Now that every thing was all done with the dash it was time to re-install it in its final position. Testing again brought the wipers to operate with the headlights but only one swipe and return each time the lights are switched on. Looks like next weekend the dash will have to be removed again to finally solve this issue.

Well I finally found the neutral issue that was causing the wipers to operate when the head lights were switched on. In my case the neutral attached to the frame of the fuel gauge had a connector further along the wire (done by a previous owner) which had somehow come apart so after fixing this connection and testing all was now working correctly.