2007 Accord EX fob issue
Thread Starter
Joined: Jan 2025
Posts: 8
2007 Accord EX fob issue
My key fob will only work when I am right next to the car. I have replaced the battery in the fob.
Locking/unlocking the doors with the key manually works fine. The lock/unlock switch in the car works fine.
If this is a multiplexer issue, do I replace the whole multiplexer or just one/some of the fuses?
Anything else I should try?
Locking/unlocking the doors with the key manually works fine. The lock/unlock switch in the car works fine.
If this is a multiplexer issue, do I replace the whole multiplexer or just one/some of the fuses?
Anything else I should try?
Super Moderator
Joined: Sep 2006
Posts: 16,328
From: Houston, TX
Overall, I wouldn't replace anything until you do more investigating.
Right now you don't know if the issue is with the vehicle or the fob. Do you have another fob to try?
This is not likely a fuse problem, because fuses tend to protect several electrical items. You'd notice other items not working if a fuse was blown like the doors would not lock/unlock at all with a fuse blown on that circuit.
Right now you don't know if the issue is with the vehicle or the fob. Do you have another fob to try?
This is not likely a fuse problem, because fuses tend to protect several electrical items. You'd notice other items not working if a fuse was blown like the doors would not lock/unlock at all with a fuse blown on that circuit.
Thread Starter
Joined: Jan 2025
Posts: 8
Overall, I wouldn't replace anything until you do more investigating.
Right now you don't know if the issue is with the vehicle or the fob. Do you have another fob to try?
This is not likely a fuse problem, because fuses tend to protect several electrical items. You'd notice other items not working if a fuse was blown like the doors would not lock/unlock at all with a fuse blown on that circuit.
Right now you don't know if the issue is with the vehicle or the fob. Do you have another fob to try?
This is not likely a fuse problem, because fuses tend to protect several electrical items. You'd notice other items not working if a fuse was blown like the doors would not lock/unlock at all with a fuse blown on that circuit.
Super Moderator
Joined: Sep 2006
Posts: 16,328
From: Houston, TX
The electronics in the car are working, so I'd lean towards a fob issue. It is either integrated into your key or a stand alone that gets banged around over time. Plus your doors do lock/unlock, so the car's electronics are working.
I think parts stores have testers for fob signals. You might want to call first to verify they can test them, then stop by and see if your fob is giving a weak signal. Search youtube for Honda Key Fob Fix When No Signal or Fresh Battery Fails. They show how to adjust the contacts and I'd probably clean the contact points with a mild abrasive like steel wool or 1000 grit sand paper to ensure the battery is also making good contact with the circuit board. You can look at the circuit board for obvious corrosion or cracked solder joints.
The antenna inside your car that detects your fob is integrated into the driver's master window switch, so you wouldn't have to mess with the MICU.
I think parts stores have testers for fob signals. You might want to call first to verify they can test them, then stop by and see if your fob is giving a weak signal. Search youtube for Honda Key Fob Fix When No Signal or Fresh Battery Fails. They show how to adjust the contacts and I'd probably clean the contact points with a mild abrasive like steel wool or 1000 grit sand paper to ensure the battery is also making good contact with the circuit board. You can look at the circuit board for obvious corrosion or cracked solder joints.
The antenna inside your car that detects your fob is integrated into the driver's master window switch, so you wouldn't have to mess with the MICU.
Thread Starter
Joined: Jan 2025
Posts: 8
The electronics in the car are working, so I'd lean towards a fob issue. It is either integrated into your key or a stand alone that gets banged around over time. Plus your doors do lock/unlock, so the car's electronics are working.
I think parts stores have testers for fob signals. You might want to call first to verify they can test them, then stop by and see if your fob is giving a weak signal. Search youtube for Honda Key Fob Fix When No Signal or Fresh Battery Fails. They show how to adjust the contacts and I'd probably clean the contact points with a mild abrasive like steel wool or 1000 grit sand paper to ensure the battery is also making good contact with the circuit board. You can look at the circuit board for obvious corrosion or cracked solder joints.
The antenna inside your car that detects your fob is integrated into the driver's master window switch, so you wouldn't have to mess with the MICU.
I think parts stores have testers for fob signals. You might want to call first to verify they can test them, then stop by and see if your fob is giving a weak signal. Search youtube for Honda Key Fob Fix When No Signal or Fresh Battery Fails. They show how to adjust the contacts and I'd probably clean the contact points with a mild abrasive like steel wool or 1000 grit sand paper to ensure the battery is also making good contact with the circuit board. You can look at the circuit board for obvious corrosion or cracked solder joints.
The antenna inside your car that detects your fob is integrated into the driver's master window switch, so you wouldn't have to mess with the MICU.
Thread Starter
Joined: Jan 2025
Posts: 8
The electronics in the car are working, so I'd lean towards a fob issue. It is either integrated into your key or a stand alone that gets banged around over time. Plus your doors do lock/unlock, so the car's electronics are working.
I think parts stores have testers for fob signals. You might want to call first to verify they can test them, then stop by and see if your fob is giving a weak signal. Search youtube for Honda Key Fob Fix When No Signal or Fresh Battery Fails. They show how to adjust the contacts and I'd probably clean the contact points with a mild abrasive like steel wool or 1000 grit sand paper to ensure the battery is also making good contact with the circuit board. You can look at the circuit board for obvious corrosion or cracked solder joints.
The antenna inside your car that detects your fob is integrated into the driver's master window switch, so you wouldn't have to mess with the MICU.
I think parts stores have testers for fob signals. You might want to call first to verify they can test them, then stop by and see if your fob is giving a weak signal. Search youtube for Honda Key Fob Fix When No Signal or Fresh Battery Fails. They show how to adjust the contacts and I'd probably clean the contact points with a mild abrasive like steel wool or 1000 grit sand paper to ensure the battery is also making good contact with the circuit board. You can look at the circuit board for obvious corrosion or cracked solder joints.
The antenna inside your car that detects your fob is integrated into the driver's master window switch, so you wouldn't have to mess with the MICU.
What would be the next step? Replace the master window switch? If so, is that a DIY project?
Thanks for the advice.
Thread Starter
Joined: Jan 2025
Posts: 8
I replaced the master window switch. No dice. Same issue. What would I check next? Thanks!
Super Moderator
Joined: Sep 2006
Posts: 16,328
From: Houston, TX
The fob and the antenna in the key swtich are the only two components for the remote lock. I saw you changed the fob batteries, but it is possible you have two weak fobs. The parts stores have fob testers at the counter, so I suggest testing them to completely rule out the fob. While you are there, have them scan for codes. Hopefully their code reader can read body control module codes (B#### codes) to possibly give some direction.
The only other item I can think of is the wiring and the electrical connector to the power window switch. Look for corrosion on any of the pins. You can try a drag test on the female connectors, but you will need a pin the same size as the pins on the master switch. If you use too large a pin, then you will spread open the pins.
If you have a 12V test light, you can check the powers and grounds to the switch to check if the wires can deliver enough current to the switch. I can let you know which wires to test, because using a test light on the wrong wires can send current on a low-current curcuit and cause more problems. One weak spot on the wiring is the harness going into the driver's door where the harness could flex over the rubber boot. You can just try pulling the boot back to see if any wires have obvious damage.
The only other item I can think of is the wiring and the electrical connector to the power window switch. Look for corrosion on any of the pins. You can try a drag test on the female connectors, but you will need a pin the same size as the pins on the master switch. If you use too large a pin, then you will spread open the pins.
If you have a 12V test light, you can check the powers and grounds to the switch to check if the wires can deliver enough current to the switch. I can let you know which wires to test, because using a test light on the wrong wires can send current on a low-current curcuit and cause more problems. One weak spot on the wiring is the harness going into the driver's door where the harness could flex over the rubber boot. You can just try pulling the boot back to see if any wires have obvious damage.
Thread Starter
Joined: Jan 2025
Posts: 8
The fob and the antenna in the key swtich are the only two components for the remote lock. I saw you changed the fob batteries, but it is possible you have two weak fobs. The parts stores have fob testers at the counter, so I suggest testing them to completely rule out the fob. While you are there, have them scan for codes. Hopefully their code reader can read body control module codes (B#### codes) to possibly give some direction.
The only other item I can think of is the wiring and the electrical connector to the power window switch. Look for corrosion on any of the pins. You can try a drag test on the female connectors, but you will need a pin the same size as the pins on the master switch. If you use too large a pin, then you will spread open the pins.
If you have a 12V test light, you can check the powers and grounds to the switch to check if the wires can deliver enough current to the switch. I can let you know which wires to test, because using a test light on the wrong wires can send current on a low-current curcuit and cause more problems. One weak spot on the wiring is the harness going into the driver's door where the harness could flex over the rubber boot. You can just try pulling the boot back to see if any wires have obvious damage.
The only other item I can think of is the wiring and the electrical connector to the power window switch. Look for corrosion on any of the pins. You can try a drag test on the female connectors, but you will need a pin the same size as the pins on the master switch. If you use too large a pin, then you will spread open the pins.
If you have a 12V test light, you can check the powers and grounds to the switch to check if the wires can deliver enough current to the switch. I can let you know which wires to test, because using a test light on the wrong wires can send current on a low-current curcuit and cause more problems. One weak spot on the wiring is the harness going into the driver's door where the harness could flex over the rubber boot. You can just try pulling the boot back to see if any wires have obvious damage.
I went by the dealership. They grabbed a new key, programmed it to the car, and it had the same issue. So I *think* the fobs can be ruled out.
I thought the multiplexer was involved in this loop somehow. Is that incorrect?
I read this:
"The multiplexer in a Honda Accord is part of the Multiplex Integrated Control System. It helps manage and control various electrical functions in the car, such as lights, wipers, and door locks.
Yes, it does have something to do with the fob locking and unlocking the doors. The system detects the key fob and communicates with the multiplex control unit to lock or unlock the doors. If there's an issue with the multiplexer, it could affect the functionality of the key fob and the door locks."