Power Antenna Relay Diagram

Hello. I'm working on my cousin's 1978 Chevrolet Monte Carlo and he asked me to try and fix the power antenna. There is power and ground at the relay switch, and the wiring coming from the power antenna seems solid, but there is no movement on the mast. I disconnected the harness under the hood and wired it directly to test, and the mast moves up and down. So I think the problem is with the relay. I can hear it click, but nothing else. I can get a used replacement for $50 on ebay, but I was hoping I might be able to just use some aftermarket relays and make my own connections. The problem is, I really don't know much about relays. I have attached a picture of the wiring diagram showing the relay connections. Is there a way I can make these connections with one or two aftermarket relays? I would appreciate any help I could get. Thanks

You need a DPDT (double pole double throw) relay or two SPDT (single pole double throw) relays. For the SPDT relays, call them relay #1 and relay #2.
Connect as follows;
Relay #1.. terminal 86 to radio power antenna lead (yellow), terminal 85 to ground (black), terminal 30 to ground (black), terminal 87 to antenna (grey), terminal 87a to antenna (green) AND relay #2 terminal 87.
Relay #2.. terminal 86 to radio antenna lead (yellow), terminal 85 to ground, terminal 30 to battery (orange), terminal 87a to antenna (white), terminal 87 (see above).

Awesome! I'm pretty sure I already have two SPDT relays at home, so this will definitely save me some money. Thank you so much for your help!!!

I wired it up like you said, and it worked perfectly! Thanks again!