4 Prong Relay ID Knowledge Challenge

[genevasm]

1980 Chevy K10, 350L, Dual Tanks...Question is is that I am trying to identify a relay (cover has been knocked off) to replace it. The relay has four external blades, 3 are in a U shape the other stand alone. The relay plugs into a socket just right of the main fuse box. Have been around to NAPA, Chevy dealer, etc. and no one can identify the module. Looked through 50 trucks at the junkyards and even went page by page in two different part books (one at NAPA and one at Checker) looking to ID the prong configuation with still no luck.

The module is 1 and 1/4 inch wide by 2 inches long and 1 and 3/8 inches high, bottom black plastic has these markings U.C.C. MADE IN CANADA; U.S. PAT. NO. 3571665,

PRONG CONFIG

                          G
     | L      B|      ____
     |          |   
           P
        ____

[Captkaos]

A picture would be alot better

[85MudMonster]

yes, A picture is worth a 1000 words.

[DnStClr]

It was a heater timer/relay. Here's an explanation from the patent office-
http://patft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=3571665,
.PN.&OS=PN/3571665,&RS=PN/3571665,
Hmm. It almosts sounds like a heater for glow plugs or an engine heater.Was the truck originally a diesel?
 Or a rear window defroster.

[85MudMonster]

That could be it, since it's next to the main fuse panel. It's got to be a relay for some option that was/is on the truck.