Is there a significance in the bottom number of this relay?

[Th1s_0ld_Truck]

I have a 1999 Ford Ranger 3.0L XLT with a drain or short somewhere in the PCM circuit. I determined this by using a test light and pulling fuses. Once found, I pulled this relay from the PCM power port for testing but apparently there are A types and B types which determine the location of the terminals. It would help to know the difference when testing with a meter. There are two other FOAB 4B192-AA relays in the box, one for the starter and one for the blower motor, but the bottom number varies by a digit. Once labeled, I would like to know if I can swap the blower motor with the I have pulled to see if it solves the problem.

 

[4x4junkie]

To me it would seem the numbers on the bottom are just a date or production code (maybe they were made one week, one month, or one year apart if there's only a single-digit difference).
The "4B192-AA" seems like would the more important number here.

If the physical pin config is the same, it's likely the same electrically as well.

 

[SenorNoob]

Searching that is weird. I get standard square 40amp 5 pin relays and rectangular relays with the same part number visibly printed on them...

 

[Th1s_0ld_Truck]

Searching that is weird. I get standard square 40amp 5 pin relays and rectangular relays with the same part number visibly printed on them...

Right. I found several results using the top number but no mention of the bottom.

 

[Th1s_0ld_Truck]

To me it would seem the numbers on the bottom are just a date or production code (maybe they were made one week, one month, or one year apart if there's only a single-digit difference).
The "4B192-AA" seems like would the more important number here.

If the physical pin config is the same, it's likely the same electrically as well.

Thanks. That was my thinking as well.

 

[Curious Hound]

That is a normal 5 pin relay, rated 40amps momentary/30amps continuous.

If removing that relay cleared up your current drain, then there is one of 2 problems. Either;

A. The contacts in that relay are welded closed and the relay needs to be replaced. (Not extremely common)

Or;

B. There is a problem with the ignition switch that is sending power to the relay coil (assuming you are testing with key off). That relay should only be energized and passing voltage to the PCM when the key is in "start or run".

 

[Th1s_0ld_Truck]

Thank you for the reply. I hope this will help to clear thing up.
Testing was done with the negative cable removed from the battery. The test light is clipped to the negative cable and light probe clamped to negative battery post.
Initially the test light is very bright. If I remove the 50A junction panel fuse circled in purple, the light goes very dim but not out. Since the 50A fuse is the for panel in the cab I was led to believe the problem was there. However, I have removed and reinserted every fuse from the inside panel and the light remained unchanged. Leaving the 50A fuse out, if I remove the 10A PCM fuse, also circled in purple, the light goes out.
Leaving the 50A out for now and the 10A in, I disconnected at the point circled in yellow (I don't know the name) and the light went out. Reconnecting here and then disconnecting at the PCM module circled in red the light goes out here as well.
Reconnecting the PCM module and moving into the cab I disconnected the GEM and the light remained on. Opposite that circled in blue (again I don't know the proper term) when disconnected the light remained on.

The two fuses mentioned were discovered by process of elimination.