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Username Post: LED Bulbs with Incandescent?        (Topic#360760)
scrambldcj8 
"2nd Year" Silver Supporting Member
Posts: 2567
scrambldcj8
Loc: Belchertown, MA
Reg: 04-06-03
05-01-20 05:15 PM - Post#2792558    

I know with LEDs, a compatible flasher needs to be used due to it thinking a bulb is out (low draw) causing a rapid flash....that is my understanding.
If add an LED at the end of a circuit with incandescent bulbs ahead of the LED will I have any issues. Thanks in advance.

Edit, I am talking about marker/running lights and turn signals.



Edited by scrambldcj8 on 05-01-20 05:21 PM. Reason for edit: No reason given.

 


acardon 
Ultra Senior Member
Posts: 11379
acardon
Loc: DFW TEXAS
Reg: 03-25-05
05-01-20 06:21 PM - Post#2792567    
    In response to scrambldcj8

Bulbs are wired in parallel, not in series, so there is no "ahead" of each other. The flasher depends on the total current draw, so anytime you replace a incandescent with a LED, you lower the current draw (load), so the flasher will not work as designed. Turn signals and emergency flashers are the only ones affected. Running lights and some side markers aren't wired to a flasher.

Don
66 Corvair (driving)
57 2dr HT (driving)
56 2dr HT (waiting to be restored)


 
scrambldcj8 
"2nd Year" Silver Supporting Member
Posts: 2567
scrambldcj8
Loc: Belchertown, MA
Reg: 04-06-03
05-02-20 04:27 AM - Post#2792598    
    In response to acardon

  • acardon]so anytime you replace a incandescent with a LED, you lower the current draw (load), so the flasher will not work as designed. quote Said:


OK, but if I have incandescent bulbs still in place will it work alright with a standard flasher?
ie: I am adding an LED into the circuit along with incandescent bulbs. My thinking is the standard flasher might not notice the lower draw of the LED because the incand bulb is still in place at another socket? Thanks for the response!




 
someotherguy 
Senior Moderator
Posts: 29176
someotherguy
Age: 50
Loc: Texas
Reg: 08-01-03
05-02-20 07:09 AM - Post#2792611    
    In response to scrambldcj8

When mixing, it's trial and error as to whether everything will behave. Which vehicle are we talking about? In the case of a GMT400 truck, sometimes LED's in the signals will affect an incandescent corner bulb adversely (dim glow full time.)

You don't necessarily need to buy a flasher, or install a resistor. Many of the stock flashers can be easily modified to cancel any hyperflash. However, if you're leaving the main bulbs as incandescent and adding LED's, you most likely won't have any issue with the flasher.

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
wagonman100 
Super Senior Member
Posts: 14551
wagonman100
Loc: Baltimore, MD
Reg: 11-27-04
05-02-20 11:57 AM - Post#2792629    
    In response to someotherguy

You might not have any problems adding an LED further along the line. But why do you want to cut into the wiring when you can just get a flasher for the LEDs and everything is plug and play?

Jay
Friends don’t let friends drive Fords.

1999 Silverado Z71 4X4 extra-cab short bed
1983 Malibu Fauxmad - tubbed
1978 El Camino Kustomized
1972 Monte Carlo
1957 210 handyman wagon
1957 Nomad sport wagon
1957 Cameo Carrier


 
someotherguy 
Senior Moderator
Posts: 29176
someotherguy
Age: 50
Loc: Texas
Reg: 08-01-03
05-02-20 12:18 PM - Post#2792631    
    In response to wagonman100

I said nothing about cutting into the wiring?

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
scrambldcj8 
"2nd Year" Silver Supporting Member
Posts: 2567
scrambldcj8
Loc: Belchertown, MA
Reg: 04-06-03
05-02-20 04:02 PM - Post#2792649    
    In response to someotherguy

  • someotherguy Said:
When mixing, it's trial and error as to whether everything will behave. Which vehicle are we talking about?






Ah yes, my bad! It's my 1983 Jeep CJ (100% Chevy drivetrain though ).

Have aftermarket Gen-Right fenders which eliminate the OEM side marker/turn signal and in turn uses a stealth lite for that function which is LED. I guess I'll go ahead and give her a go. Like I said, I don't foresee any issue since the incands are still in place on the rest of the Jeep.



 
someotherguy 
Senior Moderator
Posts: 29176
someotherguy
Age: 50
Loc: Texas
Reg: 08-01-03
05-26-20 07:32 AM - Post#2794869    
    In response to scrambldcj8

I don't know if your '83 Jeep uses an electronic style flasher or the old thermal can design. If it's electronic, it probably has the same exact timer IC used in the ones our trucks have. In that case if you end up with hyperflash with the LED's installed, you can easily hack the flasher by cutting the lead to a certain pin on that IC. It's easy, and free. Can provide info if you're interested.

Or, if it's got the thermal style and you don't want to change that, you can install resistors - 6 ohm / 50 watt are the typical ones you see with the gold aluminum heat sink on them, and they're really cheap through most sources. Just mount them somewhere that won't be damaged by heat as they do get HOT while in use. Screwed to a sheetmetal inner fender, or a core support, with a little heat sink compound between is ideal.

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
wagonman100 
Super Senior Member
Posts: 14551
wagonman100
Loc: Baltimore, MD
Reg: 11-27-04
05-26-20 03:02 PM - Post#2794908    
    In response to someotherguy

  • someotherguy Said:
I said nothing about cutting into the wiring?

Richard



Not you Richard. The original poster asked about adding LED lights and keeping the incandescents in place. That would require splicing into the wiring.


Jay
Friends don’t let friends drive Fords.

1999 Silverado Z71 4X4 extra-cab short bed
1983 Malibu Fauxmad - tubbed
1978 El Camino Kustomized
1972 Monte Carlo
1957 210 handyman wagon
1957 Nomad sport wagon
1957 Cameo Carrier


 


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