Calling All Electricians

[Superman]

Here is a diagram of the Seat Belt/Brake light. I have verified this:

I have power to the red wire
I have power to the red/black wire (when the key is on)
The brown wire is connected to ground
Neither light comes on when the key is turned.

I have two relays, two dash light units and a handful of bulbs. The lights will not come on. Here is my question:

How can I test the dash warning light unit? Can I hook up test leads giving power to the red and red/black terminals, plus ground, and expect a light to illuminate?

[FrankM_]

Which year is your car ? On the schematic of a '88 it looks different, that's why I ask.

I do not know where the wire coming in on terminal 15 is coming from (presumably the key contact)? But it looks to supply the +12V to the lamps.
The seatbelt lamp is not switched by the electronics in the warning light but by the separate 'relay'.

In my case it looks like the diagram below and connects the L terminal through a diode and transistor to ground. It really doesn't use the 'relay coil' part except to make the buzzing sound.

So... normally if you connect L to ground it should light up the seatbelt warning light. But please check your partnumber on the seatbelt warning relay and the voltage rating of the bulb in the warning light assembly I would say. You could do a test by removing the seatbelt relay and bridging pin L to pin 31 (GND) with contact on.
It will only light up the seatbelt light though.
To test the handbrake light, try to ground the HB pin or the T11 junction as normally the handbrake switch justs connects this br/ye wire to ground if the HB is up.

[proporsche]

did you check if the warning light-unit does not have a bad light bulb inside??
Ivan

i c your q...remove the front red lens ,there you can see the light bulbs or use jumper wire plus and ground to lit it up...if the light bulb is kaput -with little soldering you can replace it.
here is mine spare- repaired