What's this firewall-mounted relay / solenoid for? 99 Silverado LS Z71

[czissman]

99 Silverado LS Z71 extended cab 5.3L

 

Anyone know what this relay is for? It is fitted to the firewall on an attachment point that seems made for it, and is fitted with a proper, braided factory-looking ground strap. 

[carnau]

Thats and aftermarket switch solenoid. I normally use them when installing a wench or an extra battery. You can get them as 3 terminal or 5 terminal. Just depends on what addon is on your truck what they are using that for. 

 

This is the solenoid - 3 Terminal - http://amzn.to/2nCfuPW - 5 terminal - http://amzn.to/2nzeITR

[czissman]

Good call, carnau! It was mounted to a factory ground post on one side (the side I could see when looking under the hood), which made it look factory to me. As it turns out, the other side was wasn't bolted down at all. Traced all the wires, and each were to accessories that were abandoned by the previous owner, and now I have my PAC-200 mounted there for my auxiliary battery upgrade. Appreciate the help.

[carnau]

18 minutes ago, czissman said:

Good call, carnau! It was mounted to a factory ground post on one side (the side I could see when looking under the hood), which made it look factory to me. As it turns out, the other side was wasn't bolted down at all. Traced all the wires, and each were to accessories that were abandoned by the previous owner, and now I have my PAC-200 mounted there for my auxiliary battery upgrade. Appreciate the help.

NP. I do it for the likes!