Disastrous Automotive Soldering Connections

A few weeks ago, my neighbor came to me with a problem with his 1995 GMC Sierra half-ton truck. The daytime running lights worked fine, but he had no headlights at night. We checked the Internet for suggestions.

He had also called a few mechanic friends to get their opinion, and each of them agreed that the turn signal/high beam switch on the steering column was faulty.

After several hours of struggling to get the switch out, and grumbling about the poor job that was done installing an aftermarket remote start system, we determined that we could not open the switch assembly to perform a repair. Lacking enough information to actually test the switch properly, we decided that a replacement was in order. We eventually found one for under $100 from an online source and ordered it.

The switch arrived a few days later and we installed it, only to find that the problem still existed. We pulled out the Haynes Repair Manual, went through the electrical drawings for the electrical system, and started to trace the power supply from the battery to the switch.

Most of the wire colors, but not all, were correct in the manual, which caused a few problems. Eventually, we discovered that the power stopped at the dashboard headlight power switch. This was easily pulled and we took it to the bench for a closer look.

Using an ohm meter, we found that buried in the guts of the switch was a thermal breaker that was open. There was no reset button for this. I cut the breaker out and opened it up to find that the contacts were very pitted, and the bimetal spring had no spring left in it. In order to save another $100, I replaced the breaker with an externally mounted fuse, reinstalled the switch, and everything worked once again.

I am still trying to figure out why GM would install a thermal breaker inside the dashboard switch when there are spare fuse positions in both of the fuse panels in this truck.

At the same time, we also repaired the daytime running light modules in my 2003 Honda CRV, his 1995 Honda Accord, and his wife's 1999 Honda Accord. Amazingly, all three vehicles had the same problem: The daytime running lights were intermittent.

We pulled the module out of the CRV first, and fortunately, the module was not potted, so we were able to open it. The problem was immediately apparent: several cold solder joints on one of the relays. I re-soldered every joint on the board because there was so little solder used in manufacturing that future failures were inevitable. Sure enough, the problem was solved.

We then pulled the module on his Accord and found exactly the same problem -- exactly the same pins, even! The same remedy with the same result, the problem was resolved.

Finally, we pulled the module from his wife's Accord, and discovered that while her lights were working most of the time, the exact same solder connections were cracked, soon to be a problem. Same remedy, with the same result.

We figured that by spending an hour doing all three vehicles, we probably saved $1,500, and got a better solution than by simply replacing the module. We also found that the wiring and quality of the Hondas was much better than the GMC, and the ease of access was much better, as well.

This entry was submitted by Clint Millett and edited by Rob Spiegel.

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