2003 Acura TL - Need to find switched 12 V for aftermarket DRLs

[Number_35]

I'm helping my friend out. His relative has moved here from the US with an American-spec 2003 Acura TL.

I installed a block heater, and am now installing an aftermarket DRL (daytime running lights) module so the car can be registered here.

I've installed the module (except for the 12 V supply) complete with all the other wiring. When I run a jumper to the battery's positive terminal for testing purposes, the DRL module and associated lights work as they should.

The supply needs to be switched 12 V (i.e. only present when the ignition is on), or else the DRLs would run all the time.

I was a bit dismayed to find that every fuse in the underhood fuse panel was supplied with battery voltage (i.e. full-time, not switched).

I found a 2nd fuse panel inside the car, fed by switched power.

So now I need to run a wire from the engine compartment into the cabin. Once there I'll find a way to tie into the switched-power fuse panel.

I'd prefer to not drill a hole if possible - I'm scared of hitting other wiring or the heater core (for example).

Even better, I'd love to be able to tap into a circuit under the hood with switched power.

Any thoughts on this? Thanks.

 

[brianl703]

If it has an automatic, find the hole where the clutch cable would have run through the firewall and use that for your wire.

And you can use an ATC-add-a-circuit or an ATM add-a-circuit to make your connection to the fuse panel

 

[Number_35]

If it has an automatic, find the hole where the clutch cable would have run through the firewall and use that for your wire.

And you can use an ATC-add-a-circuit or an ATM add-a-circuit to make your connection to the fuse panel

Good thoughts - thank you!

Yes, it's an automatic. I'll look for a clutch-associated blanking plate or plug. Likely would have been a hydraulic clutch.

I bought the Littelfuse add-a-circuit kit earlier today. Looks the same as the ATC one you posted.

 

[Bailes1992]

You can get modules that will provide a switched output based on the system voltage. I.e. when the alternator is spinning an providing 14v, the unit will switch on the lights.

Alternatively, is the ECU under the bonnet? If it is then that will most certainly have a switched live. Or, run a cable into the cabin and pick up the switched live from the head unit or cigarette lighter.

 

[Number_35]

You can get modules that will provide a switched output based on the system voltage. I.e. when the alternator is spinning an providing 14v, the unit will switch on the lights.

Alternatively, is the ECU under the bonnet? If it is then that will most certainly have a switched live. Or, run a cable into the cabin and pick up the switched live from the head unit or cigarette lighter.

The switched-output module is an interesting idea, but a bit of a last resort.

The problem is getting through the firewall - after that it's straightforward.

Not sure where the ECU is.

 

[Number_35]

Ran the wire through the firewall successfully.



A big thank you to Big Worm!

 

[brianl703]

Or, run a cable into the cabin and pick up the switched live from the head unit or cigarette lighter.

Then you'll have the DRLs on whenever you have the key in ACCessory. Probably not good if you want to avoid battery drain.

 

[Number_35]

Then you'll have the DRLs on whenever you have the key in ACCessory. Probably not good if you want to avoid battery drain.

True. ON would be better than ACC, but I suspect the entire subpanel is ACC. Beggars and choosers and all that ...

 

[brianl703]

True. ON would be better than ACC, but I suspect the entire subpanel is ACC. Beggars and choosers and all that ...

Look for something like a blower, compressor clutch, climate control, instrument cluster, backup light, turn signal, cruise control, power window, rear defrost, or other fuse that would not get power in ACC, only in key on.

 

[Number_35]

Look for something like a blower, compressor clutch, climate control, instrument cluster, backup light, turn signal, cruise control, power window, rear defrost, or other fuse that would not get power in ACC, only in key on.

I could only find five switched circuits - the four windows and the sunroof.

I used one of the window circuits.

There must be a 3rd fuse panel somewhere - it seems very unlikely the items you mentioned would stay on full-time. The rear-window defrost would run the battery down really fast.

 

[Number_35]

Found the 3rd fuse panel - there's a plastic panel that comes off the end of the dashboard, and is masked by the door when the door is closed. There's a fuse panel on either side - the one I found yesterday is on the passenger side, and the one I switched over to this afternoon is on the driver's side. Lots of switched-supply fuses with no time delay on the driver's side. (The power window fuses stay active for awhile after the ignition is turned off. Not ideal.)

The set-up now works as it should.

 

[Craig in Canada]

Perhaps a dumb question because I have no specific relevant Acura experience of this type - are you 100% certain that a 2003 isn't new enough for a dealer diagnostic system to program the control modules to perform DRL function? On BMWs of that era, it's just an option you can program. In BMW circles it's called "coding" and it can be done with a cell phone etc.. as well. This is popular with manufacturers because it's a programming option and not different hardware or build spec for different regions so saves cost.

Even if you had a pay a fee to a dealer or local enthusiast with the right cable and software, it would be far more elegant than aftermarket DRLs. You might be able to tell it to change any displayed information (e.g. odo, temperature, speed) to metric as well.

 

[Number_35]

Perhaps a dumb question because I have no specific relevant Acura experience of this type - are you 100% certain that a 2003 isn't new enough for a dealer diagnostic system to program the control modules to perform DRL function? On BMWs of that era, it's just an option you can program. In BMW circles it's called "coding" and it can be done with a cell phone etc.. as well. This is popular with manufacturers because it's a programming option and not different hardware or build spec for different regions so saves cost.

Even if you had a pay a fee to a dealer or local enthusiast with the right cable and software, it would be far more elegant than aftermarket DRLs. You might be able to tell it to change any displayed information (e.g. odo, temperature, speed) to metric as well.

Not a dumb question at all. I had hoped it was a simple as adding or removing a jumper and/or plugging in a fuse.

I asked a respected automotive lighting authority about this, and he replied that Honda does not make this simple or cost-effective. For one thing, he said that Honda leaves out the auxiliary wiring. For another, the MICU would have to be replaced.

The missing wiring was confirmed for me when I saw a slot in the driver's-side-of-the dash interior fuse panel, labelled "DAYLIGHT", which I assumed would be for the DRLs.

I thought "Rats, have I done all this work for nothing?" But further investigation revealed that there was no wiring behind it.

Yes, it bugs me it's not easy to activate the factory system.