Central Warning Unit Bulb Test
Rennlist Member

I confirmed the CWU is getting power at the black plug but have not went any further. Any ideas where to look?
Rennlist Member

I swapped out an unknown CWU from one of the parts cars and all is back to normal.
Best functional description of that unit seems to be in electrical files within Morehouse CD. Also have seen snippets within the annual tech releases for each model year.
I guess I'm jealous. Am more worried keeping lights burning on the tailcone. You've advanced to troubleshooting the status light for the bulb monitoring system. Congrats, but lol at my folly.
Rennlist Member

Best functional description of that unit seems to be in electrical files within Morehouse CD. Also have seen snippets within the annual tech releases for each model year.
I guess I'm jealous. Am more worried keeping lights burning on the tailcone. You've advanced to troubleshooting the status light for the bulb monitoring system. Congrats, but lol at my folly.
So this is funny to me......my 79 had a persistent problem with the stop light warning. I replaced all the bulbs with no result. So I decided to take the time with this car to test all the CWU units I have and all the bulb warning modules that I have as well.
Out of 7 bulb warning units, only 2 were good. Two had a stop light warning all the time. Two had a stop light warning that only came on when the pedal was applied and one had a tailight warning.
I also played with bulbs to purposely trigger a failure warning. The good units set off the warning light with a missing or burned out bulb but installing two different brands made no difference. This is totally not scientific. Just curious
Out of the 7 Central Warning Units. Two lacked the bulb test feature, one had no light at all and 4 were good.
So if you are pulling your hair cleaning grounds and changing bulbs, these units are certainly capable of failure and seem to exhibit that failure in different ways. I know this has been well covered before but I wanted to put a period at the end of sentence.
I changed mine out with a used new-style unit that I obtained from 928 International. Somewhat smaller, but works perfectly.


