Non AC blower motor Relay

[Smitz70]

Hey guys long time reader... 1st post.

I have read over the posts about this & all I can find are A/C setups.

I have a 1970 c10 (non AC) that has had the wiring "rearanged".

The wiring inside the truck is intact & I have a new fan switch. I know the resistor is inside the heater box.

My question is where is the relay on a Non AC truck?

There is, what appears to be a relay, above the fan motor on the engine side of the firewall; with a gorund tab screwed to the firewall and 3 wire connectors (labled L, B, & S).

Is this my fan relay? If so how is it wired?

I have one orange wire coming from the resistor through the firewall. Does this connect to the fan motor or a relay?

P.S. Pics are great, and I am color blind; so wire color may be hit or miss..

I know it's alot of questions.. Thanks in advance.

Smitz