Keyfob is not working quite right after replaced battery

[RedMk2Gti]

After 5 years from new car, the keyfob battery needed replace that sound reasonable, but after I replaced the battery, I can hardly lock/unlock the car remotely from a reasonable distance, it mean something like 3 meters from the car in any position. The only position that I can lock/unlock is about 10 cm next to the driver door , even that it not even work for every pressing of the remote key.
Mk4 guys, any idea ? Do I need to reprogrammming the keyfob after new battery is put in ? and how ?

[gpk_gti]

sounds like a bad battery connection.check that first.or is the new battery a good one?? enough charge?? I dont think you have damaged the remote at all.check those 2 things.

[RedMk2Gti]

sounds like a bad battery connection.check that first.or is the new battery a good one?? enough charge?? I dont think you have damaged the remote at all.check those 2 things.

Red light of the keyfob flash ok when I press either key, so I suppose battery connect is not a problem. The battery is new from ****?? Electronic and I don't know how is it charged

[gpk_gti]

could be not enough power coming from battery.just because its NEW doesnt mean its full charged.you can go to a watch maker or better type of electrics store.they will connect to a miniture battery tester,which checks charge.

[DubSteve]

Skimping on the Battery also doesn't help better to pay for something thats worth it and it will last.

[RedMk2Gti]

I'm sick of keep pressing at least 5 times when I unlock/lock the car, I went to bought another new battery, problem is the same. So I swap the battery with the spare keyfob one, problem is the same. But the spare keyfob works ok with all 3 battery that I have. The mean the fault wasn't the battery, it's the keyfob itself.
Anyone know where to get replacement keyfob other than dealer ? I know eBay has a lot but first I'll try locally.

[gpk_gti]

I saw my release unit first time recently.Its behind my hazard switch,thats the receiver that receives the remote signal from the keyfob.have you tried checking that unit? buying a new fob will open a can of worms as it has to be programmed to the receiver signal.
it could also be the fob switch is getting old,,like mine????

[RedMk2Gti]

George, if the receiver unit has problem both keys will have problem, that's simple logic right ? my problem is only with one key so I doubt if the receiver unit has fault. I could use the spare key from now on, but just want to keep the spare key look new