Key fob/theft deterrent

[Lbi14lbb]

2011 grand sport convertible. 53,000 miles. Automatic transmission. After being on a battery charger while I was away from my vacation home, the car started right up and I went for about an hour drive yesterday. Came home park the car go out this morning after a huge thunderstorm (important detail or not?) and the key fob does not work. Note, I do not have a traditional key for this vehicle. I only had two working programs fobs. Thinking it was a dead battery I use the manual lever with the aid of a coat hanger to open the doors. Open the hood and the battery is fully charged. The car does nothing with the proximity keys in it. After disconnecting and then reconnecting the battery, I get an initial ding and nothing gets powered. I press the button for the lock unlock and get a ding but absolutely nothing else. I stick the first of two key fobs in the glove compartment pocket. The dash lights up ready to come to life.... I press the ignition button and everything dies. I do that twice for each fob getting the same result. Now neither fob lights up the instrument cluster and I’m back to square one

No modifications to engine. Aftermarket radio and amp.

Any assistance is appreciated. Thanks.

[LLC5]

It sounds like a bad vehicle battery or loose clamps. A fully charged battery does not mean the battery is good, only that it is ready to be load tested. Have the battery load tested. What is the vehicle battery voltage at the battery when the event happens?

[Lbi14lbb]

I’ll go out and check. New development is battery disconnected for 1/2 hour reconnect and proximity key fob allows me to open the door and then kaput. Nothing. Will see what voltage is at battery. Thx for the input.

[Lbi14lbb]

Loose positive cable. Cannot tighten it Wedged screwdriver tip between terminal and clamp. Got display Fan for climate control even came o. 12.57 on meter. Same as soon as I push start button then display dies. Volts do not change. Load test and new clamp as well?

[c4c5specialist]

HI there,

I would remove the negative cable first, then remove the positive. Spread open the battery cable end so you can push the cable all the way down onto the battery post.

Tighten to 71 in lbs and you should be all good.

Replacement cables are available if the cable ends are too distorted.

Allthebest, Paul

[Lbi14lbb]

Thank you thank you thank you. Fantastic long-distance diagnosis. Tightened the cables on the terminals and she started right up! You gentlemen are truly mechanical experts and repair warriors.