Yesterday, after having worked flawlessly for 6 months following the repairs described in Reference 1, our Saturn’s fuse box failed again. Or rather, we lost power to the cigarette lighter, the fuel pump relay, the door chime, and all the other items fed by that infamous “F5” connector pin. That is the same pin that I refer to as “A5” in the blog post referenced above. In today’s post, I shall adhere to GM’s nomenclature and refer to it as “F5”.
Unlike previous failures, which seemed to be internal to the fuse box, rather than with the external F5 connection, this time the problem was clearly with a bad electrical contact at F5, which resulted in arcing, burning, melting of the plastic around F5, and ultimately loss of electrical power to essential fuel pump and ignition components, as well as power to the starter.
It is possible, even probable, that previous failures were also at F5, but there was insufficient evidence to tie the previous failures to that contact. This time, the point of failure was unmistakable; it was definitely at pin F5. And, I now think it likely that most Saturn fuse box failures will be found to be at pin F5, rather than at the internal connections, as was assumed to be the case in Reference 1.
So, it just could be that all the work that I did (see Reference 1) to make sure that the internal connections were sound might have been unnecessary. But, that effort did serve to positively exclude the possibility of internal defects, thereby making the “bad F5” diagnosis now a certainty for my wife’s Saturn, whereas before, the failures were too intermittent to pinpoint their exact location.
So, today, I’d like to document exactly what I have done to the fuse box in my wife’s Saturn to prevent F5 from ever failing again. I hope. I added a jumper wire to augment the flaky F5 connector.
Before removing the fuse box from the car, the first thing I did was to check the cigarette lighter. It didn’t work, indicating an F5 failure. I then wiggled the wire at F5 and found that the electrical contact there was intermittent. That same wire had also been checked while troubleshooting previous failures, with the result always seeming to indicate that the connection was sound. This time, it definitely was not sound.
After removing the fuse box from the car, I found additional melting around pin F5, more than had been seen previously. Unfortunately, I neglected to take a photo of that melting. Oh well…
Here’s a photo showing Pin F5 after removing the back cover from the fuse box:
Here’s a shot of the same pin after removing some of the plastic:
I used my Dremel tool with a very small carbide tip to grind away the plastic to the right of pin F5, then I used the 1/4″ wood chisel shown in the photo to remove the small amount right next to the pin that my Dremel couldn’t get to.
Next, I drill a hole in the metal strip:
Next, I slip a piece of 14 gauge wire through the drill hole:
Next, solder the #14 wire to the metal strip:
Here’s another shot of my jumper wire:
Note the shrink tubing at the blue spade connectors. Those are intended to be crimped connectors, but I don’t like crimped connections, and I wanted the ultimate in reliability, after all, this is my wife’s car, you know. So, I soldered the connectors onto the wire, and I put shrink tubing on the joints to cover the bare solder and wire next to the spade connectors.
Here’s where the other end of that white jumper wire goes:
The jumper will be connected to the heavy red wire near dead center of the photo above. That red wire has some grey-colored adhesive on it, from the electrical tape that GM put on the wiring at the factory.
Next, I remove some insulation from the red wire:
Next, I strip about 1″ of insulation off the white jumper wire and wrap it around the red wire:
Here’s a look at the joint after the glue has had a few minutes to dry:
Here we have a look at the jumper wire hanging out the side of the fuse box after reassembly:
Next is a look at the finished product, all re-installed in the Saturn:
Yes, I know there are easier ways to make this connection. Probably the easiest is to use clip-on connectors, such as in the next photo:
1. Top view, 18-14 gauge, used to connect to a male spade connector
2. Same as 1, side view.
3. Same as 1 and 2, but closed and with a male spade connector attached. Above it is an end view of the mating male spade connector.
4. Top view, 18-14 gauge, used to splice one wire to the side of another wire.
5. Side view, 10-12 gauge, same as Item 4, except for size and color.
Yes, these clip-on connectors are convenient, and they’re reliable. They work well, but I didn’t want to trust my wife’s Saturn to them. We don’t want her suffering a breakdown. Know what I mean? I wanted the ultimate in reliability, so I soldered the joint. For just about everyone else, one of those clip-on connectors should do the job just fine. If I were to use a clip-on connector, Item #4 would be my choice.
Actually, I think I’d use three of Item #4. I’d use one at the end of the jumper wire, as it’s designed to be used. Then, for the other two connectors, I’d drill out the “stop” that’s part-way down one side of each connector, and I’d place those two connectors on the wires also. That way, there would be three of those connectors to share the load, making the whole assembly far more reliable. If I’d thought of this earlier, I’d have done this to my wife’s Saturn, rather than that hideous soldering job. With three of the connectors sharing the load, the probability of failure would be so remote that I’m pretty sure there would never be a failure.
You can buy such connectors at any hardware store.
Another way to make the splice would be to cut the red wire, strip about 3/4″ off each end of the cut, twist them together, solder them, and put some shrink tubing over the joint. Other possibilities abound. Some people might even use a wire nut, and that would work okay too, but, well, it just isn’t right…
So, the question is: Is it necessary to disassemble the fuse box and solder all the internal joints? And the answer is, I don’t know the answer. I feel better knowing that my wife’s fuse box has been soldered. I have confidence that hers will not fail her unexpectedly a hundred miles from home. And, by having already done that work to her fuse box, it was easy to take it apart and install my jumper wire. It would not be as easy to install that jumper wire otherwise.
If I were faced with fixing another one, I would assume that the internal connections were all good and try just installing a jumper wire first. Only if there were more failures after fixing the F5 connection would I remove the cover plates and solder all the internal connections.
I would try to just remove enough plastic from around Pin F5 to install the jumper. That wire would most probably be installed in a hole drilled in the same spot as shown in the photos above, but I would make that hole without removing the cover plates, the plates that contain all those bare wire. If I do this at a later date, I’ll post the photos.