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Some background: My HFL stopped working one day. Quick Google revealed that baking at 390 for 8 minutes liquefies the solder and fixes the issue. This did repair my problem, but a week later I was getting the typical parasitic draw and killing my battery. This issue is that I didn't want to keep baking it every so often, never knowing when I walk to my car if it will not start.

So, I did some thinking and grabbed the test light. The HFL module receives power two ways. 1) power all the time regardless of the key in the ignition 2) power only with the key in ON position. I cut the wire receiving power all the time (taped off the live end) and spliced the other end into the wire which only has power with the key ON.

In the pic below, I cut the white wire, and attached to the purple. So now, the module doesn't have power with the key out, thus unable to kill my battery.

I have had this "fix" done for the last week without and negatives (except the module will lose power when the key is pulled, so if you are mid conversation, it will cut you off).

This fix is also much easier and quicker than the baking method (unless your module stops working of course, then baking does help)

I'm in Canada, the dealer quoted me $840 for the part alone.
 

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Thanks. Looks great. I might want to try this later. Just want to make sure. The wire you cut is on the HFL side or on the car/harness side? I wish it is on the HFL side. That way it is a no brainer. If it is on the car side, I am a little hesitant b/c I never want to do something irreversible to the car.

I vaguely remember that somebody added a relay to the system and solved the problem (sort of). Have you compared your approach with that one? Thanks.
 

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I haven't heard of the relay approach. I also don't see a relay being of any benefit, its the same amount of power through the wire, just from an ignition ON only source vice, all the time. (relays are used to control a large amount of power with a small amount of power being the trigger)

the connector in the pic is the one which plugs into the HFL Module. It is the "vehicle harness"

the wire I cut, can easily be "reversed" by reconnecting to where it is supposed to go. two minutes of soldering and taping.
 

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Google is my savior!

http://www.mdxers.org/forums/74-second-generation-mdx-2007-2013/68497-bluetooth-stopped-working-fixed-11.html

See post #154. All thanks go to PRGonzalez!

I once thought about doing it this way, but he did not give a very detailed instruction and Radio Shack is almost gone completely from my area. I hope somebody can come up with a more practical guide.

PS: Your solution is akin to the one suggested by GerryS in post #157.
PS2: Skirmich! Can you figure this out or replicate this? Kind of hard for me.
 

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Discussion Starter #5
Google is my savior!

http://www.mdxers.org/forums/74-second-generation-mdx-2007-2013/68497-bluetooth-stopped-working-fixed-11.html

See post #154. All thanks go to PRGonzalez!

I once thought about doing it this way, but he did not give a very detailed instruction and Radio Shack is almost gone completely from my area. I hope somebody can come up with a more practical guide.

PS: Your solution is akin to the one suggested by GerryS in post #157.
PS2: Skirmich! Can you figure this out or replicate this? Kind of hard for me.
I think my fix is easier and saves a trip to radio shack (the source). I don't believe that a relay is required, at all.

guess I didn't Google long enough LOL
 

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The relay is about $4 shipped from ebay. That is a minor issue. I bought it just now.

https://www.ebay.com/itm/232440460576

The bigger issue is that I expect to see 6 feet out of the relay, but I can only see 5 now. Also I do not know how to connect the feet to the relay and harness and card, since the space is limited. Is it going to be a mess?

But your picture is also very useful. At least I know which three wires now. Thanks.
 

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The modification with a relay looks like the attached photo. The mod that kiwi did also works in similar way. In his mod the ACC power is providing full power to the HFL unit (B+ & ACC)


With the relay, I keep the intended B+/ACC separation of the design. White wire providing B+ and purple providing ACC. Either one provide the same end result.
 

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Well this is great for the parasitic draw but it does not fix the HFL unit going completely dead.
I think that was the main reason to do the baking method as in to recover HFL functionality.
 

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The modification with a relay looks like the attached photo. The mod that kiwi did also works in similar way. In his mod the ACC power is providing full power to the HFL unit (B+ & ACC)


With the relay, I keep the intended B+/ACC separation of the design. White wire providing B+ and purple providing ACC. Either one provide the same end result.
Hi PR, thanks for the effort. This picture is not very clear. I cannot figure out all the details. Can you give us a detailed list of items to buy and some step by step guidance? Thanks. Electronics is way harder than normal mechanics for me.
 

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^ The diagram is showing both sides of the HFL connector.
The relay sits in the middle.

Basically you cut the color coded wires in the diagram and put the relay in the middle of the circuit.
Seems pretty straight forward.
 

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It looks straight forward in theory, but I have never done anything like it. What kind of wires/connector to buy, how how to put them together. etc.

The ideal way I want is to connect wires between harness holes and relay feet properly, no cutting.
Same between card and relay. But when connecting card and harness, there seems no place for the wires.
Again, I do not want to cut existing wires on the harness side. I'd rather buy a new card if that is absolutely needed.
 

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I don´t see how this mod is possible without cutting wires? unless there is a way to remove the metal clip and cable from the connector plug? I think it must be possible but seems overly complicated just for cutting some wires from the HFL Unit.
 

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The installation goes like this:


1. Buy the micro relay as suggested or any similar micro-relay.
2. Have 4 pieces of 4-inch stranded 18-22 AWG wire. Two will be used for the relay coil +12V and GRN. The other two wires will be use for the contact.
3. Have 8 pieces of 1-inch heat shrink tubing sleeves for electrical isolation.
4. Solder two wires to the relay coil terminals and isolate with two pieces of heat shrink tubing.
5. Solder two wires to the relay normally open contact terminals and isolate with two pieces of heat shrink tubing.
6. Disconnect the HFL from the connector.
7. Cut the white wire (Terminal 15) to the HFL module. Do not cut too closed to the HFL connector. Strip about 3/8" of the tip of the white wires. Insert one heat shrink tubing sleeve over the relay wires soldered to the contact. Solder these wires to the white wires and use the heat shrink sleeves to isolate.
8. Cut the purple wire (Terminal 16) to the HFL. Do not cut too closed to the HFL connector. Strip about 3/8" of the tip of the purple wires. Insert one heat shrink tubing sleeve over one of the wires that go to the relay coil. Twist the purple wires together with the one wire going to the relay coil. Solder the wires and use the heat shrink sleeve to isolate.
9. Cut the black wire (Terminal 1) to the HFL. Do not cut too closed to the HFL connector. Strip about 3/8" of the tip of the purple wires. Insert one heat shrink tubing sleeve over the available wire that go to the relay coil. Twist the black wires together with the one wire going to the relay coil. Solder the wires and use the heat shrink sleeve to isolate.
10. Reconnect the HFL to the connector.


I hope it helps and that my description is understandable and easy to follow.
 

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Man I wish this would work for me but as skirmich said, mine went completely dead on me. So much for that!
 

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Man I wish this would work for me but as skirmich said, mine went completely dead on me. So much for that!
I installed the relay with the failed module. It worked for a while until the Bluetooth was not linking anymore. Then I replaced the HFL module but left the relay in place. I believe the total disconnection not only will extend the life of the new module but it will prevent a battery drain if the new module fails as the original.
 

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Has anyone ever toyed with the idea of adding a small 12V fan to the HFL unit?

I know the box can get quite hot. I will be replacing a 10mm x 40mm fan in my NVR and see if I can add that to the case to keep the components inside the box cool.

That would mean cutting the box and affixing the fan to it.

Canadian @kiwi I like your idea of removing the constant 12V to the HFL. It will be something I'll be looking into. At the moment the HFL is just sitting in my basement.
 

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Some background: My HFL stopped working one day. Quick Google revealed that baking at 390 for 8 minutes liquefies the solder and fixes the issue. This did repair my problem, but a week later I was getting the typical parasitic draw and killing my battery. This issue is that I didn't want to keep baking it every so often, never knowing when I walk to my car if it will not start.

So, I did some thinking and grabbed the test light. The HFL module receives power two ways. 1) power all the time regardless of the key in the ignition 2) power only with the key in ON position. I cut the wire receiving power all the time (taped off the live end) and spliced the other end into the wire which only has power with the key ON.

In the pic below, I cut the white wire, and attached to the purple. So now, the module doesn't have power with the key out, thus unable to kill my battery.

I have had this "fix" done for the last week without and negatives (except the module will lose power when the key is pulled, so if you are mid conversation, it will cut you off).

This fix is also much easier and quicker than the baking method (unless your module stops working of course, then baking does help)

I'm in Canada, the dealer quoted me $840 for the part alone.
Why can't I open pictures on this site?

Here is the error:

Forbidden
You don't have permission to access /forums/vbseo.php on this server.
 
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