My car does not boost unless disconnect and connect the battery neg.

there is no telling what would happen! could blow the main fuse and other fuses and even some electronics,sensors and possibly the main brain(computer)!!! you need a cheap test light to test ALL fuses.. you can check em ALL in less than 5 minutes! copy and paste this link................................................................................................................................................................... How to Jumpstart a Vehicle: 15 Steps (with Pictures) www.wikihow.com/Jumpstart-a-Vehicle

Thanks for the reply. The thing is I don't need jumper start my car . The trick to boost is disconnect/connect the neg. post of my car battery. It is like 'reset' something. What I am wondering is what could be possible causes that I can check further. I doubt fuse issue because once car is boosted it can boost normally next time within a few minutes off. but It can not after it turned off longer than hours.

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I have narrowed issue after testing amp while power is off. Here is what I have: If all fuses are in, Amp reads 1.3 (A) then stop at 740mA). if pull both RDO fuse and BFC BATT fuse, the amp reads 440mA then stops at 14mA. If only pull BFC BATT fuse out from left I/P and all other fuses in, AMP reads 1.3 (A)then stop at 640mA. If only pull RDO BATT fuse out from right I/P and all other fuses in, Amp reads 1.3 (A) then stop at 740mA. What is the next step I should go to find where the problem is? Thanks!