Outbound Traffic Manage via eBGP

Question:

We are using multihomed eBGP in WS-C3750X-48T-L Price single Router from multiple ISPs bandwidth for internet.

We have our own IP Address , at present our oubound traffic going throug ISP 1 , when ISP-1 b/w goes down then it will autometic traffic going throug ISP-2 bydefault.

But our required when ISP-1 B/W goes down our all outbound traffic will going throug ISP-3 inplace of ISP-2.

Answer:

Another option is to specify weight - with again giving  the higher vaule to the most preferred path.

Local pref on a single router is a possibility but as I understand it, It would usually be best utilised with ibgp peering-

Just to clarify - do you mean when the link on ISP1 goes down? It is just that you said "when ISP-1 b/w goes down" which could be interpreted differently.
It would be helpful if you could share your existing configs but the solution that springs to mind is to use local preference on the BGP learned routes with ISP1 routes having a higher WS-C3750X-24T-S local preference than ISP3.