Well, I think I found the right relay for the job....I am getting close I can feel it.
Here is the diagram of the new relay I bought:
so this is what I am thinking:
30 - Power Supply
85 - Ground
86 - Dome tap #5
87a - Left open
87 - Cathodes
Remember that Dome tap #5 always has power till the light goes on. So, when the light does go on, #5 tap will loose power, the swtich will go to 87 and power my cathodes under the dash. Thus acheiving the end goal.
I will give this a go later tonight and will hopefully post back...maybe even with a How to(?)
FTW !!