1989 Chevy Headlight Woes Please Help

[Noreastern Rider]

So I was driving my truck to work yesterday and my Radio goes out, but I didn't have any time to troubleshoot it because I was late to work. But then I go to drive home last night and I realize that the headlights and parking lights are not working. So I've been trying to troubleshoot this all day but I am stumped. I checked the courtesy fuse and the parking light fuse and they were not blown. So I got out my meter, now all the fuses are reading 12 to 12.5 volts on the battery side but the courtesy light fuse and the parking light fuse read 9.5 volts. But when you try to turn on the headlights, parking lights, or open either door that voltage disappears.
Now I removed the headlight switch and confirmed that it was working properly by testing for continuity. So I the put power to the headlight wire and the parking lamp wire they both worked fine.

Has anyone else ran into this problem before?

Thanks
Vin

[ChevyTech]

Check all the connections under the hood on the passenger side of the firewall at the junction block which may still have a black plastic cover over it. There are fusible links at the junction block also. I have found several trucks with connection problems at the junction block studs when the nuts were not all that loose, but I have also found many with loose nuts.

Fusible links are pieces of wire that burn to protect the circuit. Feel all the wires at the junction block to see if you find a bad one. They could be melted off inside and hard and stiff near the ends.

I see it’s your first post. Welcome to the message board.

[Noreastern Rider]

Chevytech thanks for the response, Yea Ive been lurking around for a while now but this was actually the first time that I couldn't find the answer on the board, I've found this forum very helpful. And it looks like you've found my problem I did not realize that the wires there were fusible links.

Thanks again
Vin

[ChevLoRay]

ChevyTech to the rescue!! We're lucky to have him help out on this forum.

[ChevyTech]

Originally Posted by Noreastern Rider

Chevytech thanks for the response, Yea Ive been lurking around for a while now but this was actually the first time that I couldn't find the answer on the board, I've found this forum very helpful. And it looks like you've found my problem I did not realize that the wires there were fusible links.

Thanks again
Vin

You’re welcome!

I’m glad you find the site helpful.