Hello all, this is my first post here but I've been a long time reader.

Car specs

1993 Volvo 940 Turbo (Wagon).

The problem

TL;DR: Basically, My headlights don't turn on, and I also lose power to the dash lights and parking lights (front and back) when I try to turn my headlights on.

With the car on, when I turn the light switch to the mid position (parking lights), the parking lights in the front and back come on as expected, as well as the dash lights. When I turn the light switch to the right position (headlights), The headlights DONT come on, and the parking lights in the front and back (which were previously on) shut OFF. The dash lights also shut OFF. The high beams work as expected, no matter what position the light switch is in. The problem I'm experiencing seems identical to one described in a separate thread here

Further background & context

This issue arose immediately after I finished putting in a new stereo (which required taking out the center console and exposing the fuse and relay.

What I've tested

Using a volt meter:

• I'm not getting any power to fuse 19 or 20 (the fuses for the Left and right Low beams, respectively). The fuses don't look blown.
• I am getting some power to the headlight relay (the one in the K position): The bottom middle pin always gets power, but no other pins are getting power, even when I turn the headlights on via the light switch (far right position). I would expect that some pin should go high when I turn the headlights on via the light switch.

What I don't know

Given the timing of my issue, I suspect that I accidentally bumped or disconnected a connection/wire somewhere while working on the car. I suspect that this would be upstream to the fusebox (since fuses 19 and 20 are not getting any power). But I am not sure what specifically to look/check for next. Any insights, suggestions are welcome.


Thank you in advance!

Scott

 

If you don't have the car's wiring diagrams try https://ozvolvo.org/archive. Trying to keep all those circuits in your head while working will lead to early burn out. Pick one function that's not working and follow that circuit. Start from the battery and check every connection along the way.

If you come to a relay that's not working make a sharp turn and follow the relay's trigger circuit. You can also try jumpering the relay and see if the problem circuit starts working.

 

You might find helpful headlamp relay info on this page

https://www.240turbo.com/headlightrelay.html

 

SOLVED. Thanks @Johnsf and @hoonk . More details below.


As was pointed out on this thread , for some reason, the circuit to the headlights was connected to the original stereo in the Volvo 940's.

When I bought this Volvo, the stereo was already out, and I just put an after market stereo in. After I hooked it up, there was an extra cable that I presume hooked into the original stereo, which I no longer needed (it didn't connect to my after market stereo). I tested the cables with a volt meter and it seemed dead. So to clean things up I cut it and taped it up (not knowing what I was getting myself into...) :

Below is a photo. The Yellow/White wire in that connector were actually wired together and completed a circuit that was critical for headlight function.. As you can see in the photos, I had previously snipped the connector, so I ended up having to twist the Yellow/White wires back together and tape them up so that the circuit remained intact.

And Voila.... The headlights work as expected again..



As you can see I snipped The connector on the left. Those yellow/white wires complete the headlight circuit and are critical for headlight function.




You can tell that the Yellow/White wires were in the same socket together, whereas the other wires were in their own socket. To fix my mistake I twisted the wires together and taped them up.



The headlight circuit being routed through the radio really blows my mind. I've never seen anything like that!

Scott