My '79 40 didn't have the blower for the carb when I got it about 6 years ago. Until recently I was ignoring my hard-starts after the engine was warm and then sat for a while. I started reading the LONG threads about guys on MUD getting their carb coolers working and having much success with ending their hot start issues.
I ordered a blower from the classified ads and installed it on the existing bracket at the louver on the driver's side. Thinking everything else was good, I soon found that the squirrel cage motor would not operate on the truck, but worked when directly on 12 volts. (By the way, I initially hooked up the motor to the battery and thought the output was pretty anemic. I tried reversing the polarity and made a huge difference.) Anyway it turns out that I had the usual problems, blown 5 amp fuse with the yellow tape around it behind my instrument cluster, also had a bad M3 relay (same as still used on fairly recent Lexus car headlights), and the controller module was not functioning.
Following the suggestions of earlier postings, I pried open the controller box and re-flowed the solder on all of the pins on the green plug socket. This socket takes a lot of stress when plugging and unplugging and mine had several cracks around the solder points. Put it all back together and still didn't work. Took the board apart again and checked the diodes, all checked good enough. Really getting desperate, I started looking at the copper traces and found two cracks on the traces near the socket. One was lengthwise on the trace and not a problem, but one crack completely isolated several components from the socket. The attached photos show the crack before and after I scraped the coating off the trace and ran some solder to complete the circuit. Success! It worked just fine after this. I just wanted to pass on the possibility of cracks in the board being an easily repaired solution.
I ordered a blower from the classified ads and installed it on the existing bracket at the louver on the driver's side. Thinking everything else was good, I soon found that the squirrel cage motor would not operate on the truck, but worked when directly on 12 volts. (By the way, I initially hooked up the motor to the battery and thought the output was pretty anemic. I tried reversing the polarity and made a huge difference.) Anyway it turns out that I had the usual problems, blown 5 amp fuse with the yellow tape around it behind my instrument cluster, also had a bad M3 relay (same as still used on fairly recent Lexus car headlights), and the controller module was not functioning.
Following the suggestions of earlier postings, I pried open the controller box and re-flowed the solder on all of the pins on the green plug socket. This socket takes a lot of stress when plugging and unplugging and mine had several cracks around the solder points. Put it all back together and still didn't work. Took the board apart again and checked the diodes, all checked good enough. Really getting desperate, I started looking at the copper traces and found two cracks on the traces near the socket. One was lengthwise on the trace and not a problem, but one crack completely isolated several components from the socket. The attached photos show the crack before and after I scraped the coating off the trace and ran some solder to complete the circuit. Success! It worked just fine after this. I just wanted to pass on the possibility of cracks in the board being an easily repaired solution.