Cigarette Lighter and Blower Relay Wiring Questions

[Classics Fan]

I have a 1971 Jimmy that I discovered the cigarette lighter had stopped working. Related to that I believe after investigating and doing some research, recently I noticed a burning smell when the heater blower speed was set on high. It goes away on lower settings. Anyway when I looked at the cigarette connection on the fuse panel I found that connector (orange wire) had some melting. I replaced the connector but the red wire at the back of the lighter still doesn’t have power.

That led me to doing some research and I found the first photo below on a different forum post. It shows both an orange wire and red wire at the CIG fuse panel connection. The second photo is my panel. You can see it has only the orange wire (blue arrow) however, there is also a separate red wire (yellow arrow) I found disconnected that I thought might be the power to the lighter. I connected it to the fuse panel at the post that is directly below the cluster connector (red arrow, it has unswitched power) but still nothing at the lighter.

Anyone have any ideas on what could be going on here? The lighter worked until it didn’t. I hadn’t removed or disconnected any wires at the fuse panel. One thing I found strange is the CIG connection is unfused. Is there a fuse or fusible link somewhere else? I tried to trace the red wire back from the lighter but it disappears behind the dash panel and I didn’t want to pull the panel until I had some answers to my questions.

Thanks in advance for any insight.

[HO455]

Its my experience that GM typically doesn't fuse the cigarette lighter which can be problematic. I had a lighter short out internally while driving down the freeway in my old S10.

I don't smoke and never used the lighter but out of the blue one day smoke starts billowing out from the dash area where the lighter is. Needless to say I made a sharp right to the side of the road and started tearing wires out of the dash.

I believe that the cigarette lighter and the high speed fan power can share the same connector at the fuse panel. The link explains the circuit as well as has the wiring diagram.

http://67-72chevytrucks.com/vboard/s...d.php?t=705082

[Classics Fan]

So to follow-up and close this post: today I looked closer at the disconnected red wire near the fuse panel and to me it just had to be the lighter wire. I reconnected it to the same blade as yesterday that I thought was constant 12 volts, turned the ignition to Run and was happy to find power to the lighter. I then connected the red wire to the piggyback connector on the orange wire (high blower relay), installed an inline 20 amp fuse to protect them and called it good. I feel much better having this relatively high-amp wire protected. No more melting!

[1970cstblazer]

The lighter circuit is protected by the large fusible link in the main harness by the battery.

[HO455]

No melting is good! Best to keep the smoke inside the wires so everything works.

[Classics Fan]

Originally Posted by 1970cstblazer

The lighter circuit is protected by the large fusible link in the main harness by the battery.

If that’s the case wouldn’t the blower relay circuit also be protected since they get power from the same blade on the fuse panel? If so why did I experience melting on the relay fuse panel connector?