My remote starter hand held unit is 5 years old and is starting to not work as well. Where can I get a replacement?

I understand your frustration. Call 1 (888) 427-3973 if these do not work.

1) The on/off switch on the fireplace and/or wall may be in the on position. This will over ride the remote control feature.
2) The remote is in the thermostat mode (SMART-STAT and RCT-MLT models) and the temperature of the room has not exceeded the desired temperature setting by 2 degrees Fahrenheit or 1 degree Celsius.
3) Batteries in the hand-held transmitter are old and underpowered. May work up close and will not work a few feet away.
4) Hand-held transmitter is outside of the 25' of operation.
5) Hand-held transmitter has been dropped and the frequency has been moved off the frequency of the receiver.

http://www.heatnglo.com/Owner-Resources/Troubleshooting-and-FAQs/Common-Questions/Remote-Controls.aspx

Stock Kichler ceiling fan c. 2006, works with replacement remote control 337001WH hand-held unit from Amazon 2013. Started running backwards when two remotes were activated at the same time by accident. Random button pushing on two remotes simultaneously got it to go back to forward. (Apparently original remote hand-held transmitter had forward/reverse setting, but the substitute 337001WH transmitter doesn't. When two transmitters run at the same time, the fwd/rev code may be decoded in the collisions at the receiver. Thank goodness!)

Taking apart the hand held remote won't serve any real purpose as none of the parts inside are replaceable. Since you have 3 different units, with 3 different hand held remote. I'm wondering, if perhaps, you're using the wrong remote on that one unit. As each one has a different remote code.
In addition, I have learned from experience, that if the display screen on the hand held works, the problem is not in the hand held. Now, that's not to say, Operator Error can't play a role in it. But, most times, it's the receiver in the unit,that may be causing the problem. Or the hand held is to far away or something is blocking the signal in between.

Almost every appliance we sell, has a radio frequency remote control. The most problems we incur is with weak or dead batteries or operator error. The problem with batteries is that you don't now how long they sat in a warehouse, before making to a retail outlet and then how long they sat on the shelves there, before they were sold. They may have enough power to activate the handheld remote, but not enough to transmit a strong signal. So, check the strength of the new batteries you installed.

Hope this helps and thanks for choosing FixYa.

Hand held remote control units have batteries installed in them. It sounds like your batteries are run down. Replace them.

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Regards,
Yavacotech

under the dash remove the main fuse or fuses from the main module for 2 min then replace and reprogram your remote

it is possible that when you programmed the car remotes you erased the pairing between your hand held remotes and the unit. Follow the instructions to pair the remotes again and you should be good to go.

When did your remote and keypad quit working? Was it when you programmed the Homelink? It sure sounds like you have a bad logic board.

It sounds like you have a bad starter solenoid. You did not state the make or year of your truck, but Fords had a separate starter solenoid attached to the inner fender under the hood usually near the battery. It is a round, black device about an 1 1/2 inch in diameter with several wires & cables attached. A battery cable is attached to one side of it and a cable to the starter comes off the other side. Usually there are to other smaller wires attached to it that come from the ignition circuit. By touching one of the ignition wire posts to the starter motor post using a screwdriver, you can "Jump" the solenoid and cause the starter motor to turn. If this sounds like what you are doing, then you are essentially performing manually what the starter solenoid should be doing automatically every time you turn the ignition switch to the start position. These units are inexpensive and readily available at any auto parts store. However, before replacing, I would check all the connections to make sure they are free of corrosion and are tight and secure. Other models and manufacturers have the starter solenoid mounted on the starter motor itself. This doesn't sound like you case because you would have to crawl under the truck to accomplish this jumping task. I hope this helps you.
Mark T

Could be.
Yes, change the battery in the hand held unit first.

Next could be the control unit.
Next could be that there is something brocasting in the area that is near the same frequency.
Does this only happen at home? Or has it happened in other areas also?

Is this a factory unit? Or an aftermarket install?

To turn on the remote you must press the POWER and LOCK buttons together.