Update [I did´nt drove it since Jan]:
Actually it
all didn´t work
! As I only drove some miles it did not show up. This is my investigation. Maybe it did never really work- at least since the replacement engine went in last year. I remember that the Fuel Filter light did came on in the past, but "no issue". This probably due to stop and go and never really loger time wot.
The Fuel Filter light is directly behind the steering wheel, so it cannot be seen in
my normal driving position.
- I investigated a false automatic fuse that I installed in the setup as seeing above. The fuse was sitting on close position but was actually open New one in and measured ~12 V going out of the fuse "box".
I recently wanted to to dive it and after 20 minutes and ~ 10 miles the light came on. Goes on and off (off throttle).
- So I measured again. 12v going out of the fuse into the relay. Filter light on!
- electric pump directly to the battery: Pump running - fuel filter light goes off. Though I did not drive it like that.
- on #30 @ the relay 12v are present.
- when engine is running, I measured 87 (pink cable I am correct) no voltage!
- when engine is running, I measured 86 (if I am correct). The yellow one is the one coming from the GP relay to initialize the relay. 3-4 volt.
- This is for sure not enough, though i haven´t read the specs of this relay. Maybe specification is more like amperage - don´t know. Probably a broken cable, this is strange.... I measured ~10-12 volt at the post of the relay, where this cable is connected.
The initial problem was probably
not the missing relay but the drop in voltage in this cable. Before the whole mess with this truck [2014-2017] I installed the new pump exactly like the old facet was installed.
BUT a new engine was installed and with it a new cable connection. I installed it with a fuse inline - now I cannot see the now installed cable connection. Maybe good - maybe not. Maybe the, hopefully installed, fuse is just gone. But in that case there should be no voltage instead of 3 volt.
Raining today - I will look for it tomorrow.
What can I use instead of the GP relay to trigger the pump? IP shut-off was mentioned ...