Okay, so my junk keeps giving me CELs about the #2 GP being bad. I've used my volt meter to test them all, working up to the point of just unplugging the relay and using the amperage range on the meter I got 15A on all 4 of them.
One lead on the battery positive post, the other on the pin in the relay connector. So I know everything else in the system is fine and dandy.
So I looked around and I can get a new bosch relay for $45ish through work. Figure hell, what's there to lose and took mine apart to see if I could screw with it.
Put a couple razor blades in the tabs and got the innards out, and sure enough there ain't no relay contacts. There are three power transistors though. Simple enough and kinda cool that they went solid state. All three test good, so I look a little further and sure enough there's an aluminum spacer in the buss bar on the drain of all 3, and it came that way intentionally. For whatever reason they don't want #2 to have a transistor directly feeding it, but instead they have the thing feed power to it through the circuit board and then up along another bus bar to the connector.
They also have 4 SMD resistors (1 K ohm) from each GP pin on the non transistor end of the bars to the GP controller chip. They must measure volt drop across the bars to see if one's drawing less current. All good and ****, except that one of them has a slightly longer path before that resistor, and sure enough it is the one that keeps giving me ****.
So, do I add another NPN power transistor to it, or just tie all 4 bars together at the "volt sense" trace?
I'm leaning toward the option that makes the controller "dumb" and think that all GPs are good all the time.
One lead on the battery positive post, the other on the pin in the relay connector. So I know everything else in the system is fine and dandy.
So I looked around and I can get a new bosch relay for $45ish through work. Figure hell, what's there to lose and took mine apart to see if I could screw with it.
Put a couple razor blades in the tabs and got the innards out, and sure enough there ain't no relay contacts. There are three power transistors though. Simple enough and kinda cool that they went solid state. All three test good, so I look a little further and sure enough there's an aluminum spacer in the buss bar on the drain of all 3, and it came that way intentionally. For whatever reason they don't want #2 to have a transistor directly feeding it, but instead they have the thing feed power to it through the circuit board and then up along another bus bar to the connector.
They also have 4 SMD resistors (1 K ohm) from each GP pin on the non transistor end of the bars to the GP controller chip. They must measure volt drop across the bars to see if one's drawing less current. All good and ****, except that one of them has a slightly longer path before that resistor, and sure enough it is the one that keeps giving me ****.
So, do I add another NPN power transistor to it, or just tie all 4 bars together at the "volt sense" trace?
I'm leaning toward the option that makes the controller "dumb" and think that all GPs are good all the time.
