In what would otherwise be minor maintenance replacing a blown taillight bulb, I discovered that the bulbs were in fact fused to the sockets. I was able to remove the backup bulb and scrub the socket with steel wool, though forgot to disconnect the wiring harness beforehand. I think the truck may have been shifted to reverse at this time so a short occurred. The symptoms as they became clear with time: the buzzer does not stop when key in ACC, the cab blower fan doesn't work, rear and turn signal lights out (luckily brake lights still work), and all dash gauges not working. I checked all the fuses (see pic) and they all seem to be unblown. As for some background, on occasion I had been noticed infrequently the dash gauges go out for a limited amount of time then come back on. Luckily I had already installed a kill switch that I can use to disconnect the battery when not driving. Could there be a relay rather than a fuse damaged that would cause this set of issues? Otherwise maybe I need to get some long wire and start patching different circuits to locate the short? Any good tutorials for diagnosing and getting after shorts in the wiring?

 

I am working on diagnosing and finding an electrical short. For this I am disconnecting the battery and bridging the gap with a test light. It is said if the test light goes on then there's a short. However, would the standard devices that usually stay on clock / radio memory cause the test light to light up or the current from these are too minimal?

 

Radio memory alone, probably not. Clock, maybe. Remember that to get get the clock to come on, the key needs to be in ACC or ON. With the key in ACC or ON, though, you'll get so much current flow, your light will come on. You need to isolate the circuit further. Move your light closer to the item suspected of causing the problem. Like to the other side of the fuse of the circuit under test.

Personally, and it's just my personal preference mind you, I'd rather use a multimeter for this sort of thing. But I spent a long time as a radar tech, and the multimeter is much more versatile. If you're searching for a short in a circuit, for example, start much closer to the suspected item. I'd need to know what circuit you're looking in for a short. Like, if you have a problem with the tail lights blowing the Tail Light fuse. OK, first, isolate whether it's the left or right tail lights causing the problem. Unplug the left tail lights completely. Heck, at worst, pull all the left tail light bulbs. Still blowing the fuse? OK, you know it's the right side that has the problem.
OK, now take your multimeter and test each right side tail light circuit. Just find the one that has a short to ground, with the bulb out. Why with the bulb out? Light bulbs have a very low resistance. If you pull the bulb out of a light circuit, and you still have a short, you've found the trouble.

Checking with a noid light on the battery for a short circuit, all it can tell you is that someplace downstream of the battery, which covers a pretty wide selection, you have something drawing some current. It doesn't really tell you anything you need to know.

Does all this help any at all?
Pat☺

 

In addition to what 2ToyGuy says, consider getting a "big" bulb (like a taillight bulb) and socket, then use that to replace the fuse that keeps blowing. If you have a short, the bulb will light up "full brightness," but the current will be limited to about 1amp. The wiring will be protected and you won't end up going through a box of fuses. Then work your way through the downstream wiring, and when the bulb suddenly dims you've found the short.