So I go to accessory shop at Mahkota Cheras to check whether is it wiring problem or Horn spoil.
After checking, the technician say have to change the Horn, not wiring problem.
He charge RM 65 for 1 pair of BM Horn including wiring and relay, made in China.
If I buy my Horn - Compact Horn, workmanship RM 20, PM Horn workmanship RM 40
I decided to go to spare part shop to check for the price:
There are two type of Horn:
1) Compact Horn - RM 45 Bosch - 1 pair
http://www.lelong.com.my/bosch-fc2-compact-horn-chyee1986-163508061-2016-05-Sale-P.htm
- Online is selling at RM 50
2) BM Horn - RM 55 Bosch - 1 pair
So in the end, I go back to the shop and change the china brand PM Horn.