Motorcycle relay module unknown diodes

Thread Starter

DirtyHands

Joined Sep 19, 2019
5
I'm having issues with a project motorcycle and I believe I found the problem. There are 6 diodes on this board and they are all identical but they show different readings on my multimeter. Two of them pass voltage both ways (0.164) one of them only passes voltage one way (0.562) and one of them does not pass voltage either way and the other two I lost somewhere.

If you hold the diode with the grey stripe facing up you can see the numbers 0658 but as you can see at D3 in the pic the numbers 5 and 8 are printed sideways while 0 and 6 are right side up.

I'm having a very difficult time identifying these diodes. Maybe someone with more experience can help?
DSC_047.jpg
 

LesJones

Joined Jan 8, 2017
2,414
If you are taking measurements with the diodes in circuit you will need to take into account the effect that the rest of the circuit will have on the readings. If you can't work this out then post the FULL schematic of the board.

Les.
 

Thread Starter

DirtyHands

Joined Sep 19, 2019
5
Since I lost two of them and one is no good I was only trying to find a part number for the diodes so I can buy replacements. It seems impossible because there are only 4 numbers.
 

Thread Starter

DirtyHands

Joined Sep 19, 2019
5
It's a fuel pump relay and ignition relay. What controls the relays is the on/off switch, side stand switch, clutch switch, and neutral switch. The problem I'm having is the relay module thinks I have the side stand down and the second I lock it in gear it kills the ignition relay and the bike dies.

The only thing missing from the pic is the 14 prongs for the module to plug in to the wire harness.
 

dendad

Joined Feb 20, 2016
3,153
D3 and D5 are probably ok as they are across the relays. You will be measuring the relay coil when trying to test them.
 

Thread Starter

DirtyHands

Joined Sep 19, 2019
5
I would say you are correct about D3 and D5 because both the relays work as expected. I checked D1 in the circuit and there is no continuity in either direction. I removed D4, D6, and D2 from the circuit to get real readings because what I was getting while they were attached to the board was inconclusive. That lead to loosing one and one broke in half and I lost one half of it so I only have the one from D4.

It's a motorcycle so the battery voltage is 12.8 with a tops of maybe 15 while it's running. I think D1 D4 D6 D2 are used for the switches. That being said, a 1n400x series diode should work fine right? It only needs to block voltage in one direction and handle 15vdc.

Correct me if I'm wrong but the bigger the component the more it can handle right? The diodes on this pcb are so small they can barely fit 4 numbers around them. So a 1n4001-1n4007 being a bigger component should mean it will work?
 
Top