I have not seen this tip here....
I once learned a neat trick that the Cummins engine company now uses as a diagnostic aid. It is routinely factory installed on many of their newer electronically controlled diesel engines.
Cummins installs a "telltale" fuse between the frame and the engine block.
This is a 1/2 amp very light duty fuse. Any time a technician could suspect unknown electrical gremlins.......he need only inspect the fuse. If he finds that fuse blown, he knows that he has a faulty ground somewhere in the wiring.
I thought.........how cool is that??????

would have been smarter thinking to make it one of the newer led indicator types

but then i guess some customers would wake up to that pretty quick ...robbing them of valueable service jobs ...

but a great idea none the less.... perhaps we can do similar

put a light rated fuse between the frame ground and the battery negative terminal ....would cetainly pickup and indicate when that rotten earth on the gearbox was going intermittent huh ?

A good idea, I have changed all my fuses for LED indicator fuses as that makes it a quick spot to see if a fuse is blown.
Regards,
K-BIKE

I was toying with the idea of led indicator relays.
ever seen anything like that? a green led when relay is closed???? maybe a red one to indicate when power is available at the relay????

I specify them for PLC driven systems for industrial controls, a simple check in the switchboard tells one instantly which relay is energised a huge aid to commissioning checks.
Regards,
K-BIKE

for the standard 50A auto relay? that has LEDs?

85/86 87/87A 30 ?

i think kbike is refering to more of the cradle type relay

have seen zillions of them in my work

although lots are now going to solid state relays in 4 gang high barrier terminations fuse on top

Charlie is right that was what I was referring to but the principle is still sound with a standard auto relay if it is one that you can get the case off. With the right model of relay there should be space to fit a small LED through the case. If there was not enough space to take the leads folded down when the case was replaced an LED fixed in place with a hole large enough for the LED to poke through when the cover is replaced and a small line of silicone to fit round the diode and seal the case. That said it would be easier to mount the LED outside the case wired straight off the coil connections and fastened to the relay case. Whichever method one used all relays that were engaged would be glowing the colour of your choice. It won't tell you current is flowing through the contacts but it will tell you the relay is pulled in. The real benefit comes when you are stranded miles from anywhere with an electrical fault I reckon having indicating relays and indicating fuses should speed diagnosis a lot.
Regards,
K-BIKE