Earlier this year I bought a 1998 K1500 Silverado z71 5.7L and immediately had the transmission rebuilt.

Driving it a short time later I went to turn on my left blinker and lost all interior and exterior lights, radio, blower fan, as well as the engine started running oddly, not accelerating and skipping in the firing sequence.

I ended up replacing the dimmer, multi-function switch (connector was a little melted), and both rear taillight assemblies (right had a fault and would only work correctly after a sharp blow), and blower fan motor (it was clicking).

While this improved things there was still an obvious fault somewhere in the electrical system. Neither the family mechanic nor the local dealership could fix it. In fact, the local dealership claimed to give fixed it after charging me $600 in repairs and trying to replace both batteries that claimed were bad for another $300.

When I got it back it was running much better but was still a little iffy. The voltmeter jiggles when the left turn signal was on so I hadn't tried driving it at night in case I lost lights again.

Well, I had to try the other night and that is when I noticed I had no low-beams. Turns out they returned the vehicle to me without a daylight running light relay.

I tried to buy a new one but the local parts store didn't have any in stock so I bought a 30A to put in it. When I got home there was actually a 40a relay in the box. I bent the contacts to make it fit anyway and it seemed to work. I decided to order the proper size (25A) online.

When the 25A relay arrived in the mail I went and swapped out the 40A relay. With the 25A relay in all of the interior and exterior lights, radio, and blower fan all started sputtering like the weren't getting a steady power source. I put the 40A relay in and they started acting normal again.

I don't know if the relay also causes the engine sputtering. I havent tried to drive it with the 25A relay but it wasn't doing it when there was no relay plugged in.

I wonder if I might've just got a bad relay in the mail or if this is indicative of a fault somewhere in the lighting circuit; possibly in the convenience panel since the 25A relay sits fully in and the 40A relay just sits in enough to make contact because it really too fat to sit in it correctly.

Figure rhe fault is in the relay, the circuit somewhere other than the relay; possibly in the convenience panel itself.