4 pin relays for headlights
Ok, the problem with calling this or that is that terminology and "standards" get polluted and muddy. You would have to go back to "an original Bosh relay" as used in original OEM configuration. So far as I know they were 5 pin, that is 2 for the coil, 1 for normally open, 1 for normally closed, and 1 for the common.
But "other" configurations by "other people has resulted in all kinds of variations
One is to use larger contacts to make a heavier relay, normally open relay, which should be "4." But some makers wire what should be the normally closed pin IN PARALLEL for more current, so you no longer have a "standard" relay
Worse, some of these (some are OEM like JEEP) use LARGER contacts and don't fit some relay sockets
An example of the non standard "big" pins
Another "gotcha" Some replacements don't have internal protection diodes across the coil, and it seems (from discussions on here) that some do have diodes that are REVERSED from what should be "standard." "How to tell?" Check resistance of the coil with your ohmeter, then reverse the leads. If the resistance changes dramatically, you have an internal diode. You need to wire it correctly, or it becomes a dead short.
Below is what I know as a "standard" Bosch style relay with diode
You want the diode REVERSE biased (not conduction) so wiring is
85 --ground--marked -- in photo
86 --trigger to coil positive
30 fused power source "coming in"
87 "normally open" meaning the relay is powered to power this contact
87a "normally closed" meaning carries power when relay not powered.
==========================================================
87a is not present in a "4 pin" and is the pin that if present MAY be paralleled with 87 in a "non standard" relay
Like this
Ok, the problem with calling this or that is that terminology and "standards" get polluted and muddy. You would have to go back to "an original Bosh relay" as used in original OEM configuration. So far as I know they were 5 pin, that is 2 for the coil, 1 for normally open, 1 for normally closed, and 1 for the common.
But "other" configurations by "other people has resulted in all kinds of variations
One is to use larger contacts to make a heavier relay, normally open relay, which should be "4." But some makers wire what should be the normally closed pin IN PARALLEL for more current, so you no longer have a "standard" relay
Worse, some of these (some are OEM like JEEP) use LARGER contacts and don't fit some relay sockets
An example of the non standard "big" pins
Another "gotcha" Some replacements don't have internal protection diodes across the coil, and it seems (from discussions on here) that some do have diodes that are REVERSED from what should be "standard." "How to tell?" Check resistance of the coil with your ohmeter, then reverse the leads. If the resistance changes dramatically, you have an internal diode. You need to wire it correctly, or it becomes a dead short.
Below is what I know as a "standard" Bosch style relay with diode
You want the diode REVERSE biased (not conduction) so wiring is
85 --ground--marked -- in photo
86 --trigger to coil positive
30 fused power source "coming in"
87 "normally open" meaning the relay is powered to power this contact
87a "normally closed" meaning carries power when relay not powered.
==========================================================
87a is not present in a "4 pin" and is the pin that if present MAY be paralleled with 87 in a "non standard" relay
Like this