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  • 1965 - 1973 Classic Mustangs -General/Talk-
  • Classic Mustang Specific Tech

Headlights blink on and off

  • Thread starter Thread starter Rat Race
  • Start date Start date Aug 11, 2005
R

Rat Race

New Member
Apr 3, 2005
59
0
0
New Jersey
Aug 11, 2005
#1
  • Aug 11, 2005
  • #1
I put 100 watt H4 bulbs in my 67 coupe, and now every time I put the lights on , they work for about 10 minutes and then just blink on and off.

Is the bulb too high a wattage or is is something to do with the switch?
 

thehueypilot

Active Member
Feb 25, 2004
1,084
0
37
Medina,Tennessee
Aug 11, 2005
#2
  • Aug 11, 2005
  • #2
Rat Race said:
I put 100 watt H4 bulbs in my 67 coupe, and now every time I put the lights on , they work for about 10 minutes and then just blink on and off.

Is the bulb too high a wattage or is is something to do with the switch?
Click to expand...

It's the dimmer foot switch. It was not designed to handle double the amperage that your new lights are pulling. Painless Wiring makes a relay wiring harness that plugs into the existing connections which was designed just for this issue. I had the same issue and I can tell you it was scary the first time it happened on a dark country road. I put the new harness on and it has not done it since.
 
G

grego37

New Member
May 12, 2004
576
0
0
Fresno CA
Aug 11, 2005
#3
  • Aug 11, 2005
  • #3
ditto.
you need to run a relay, or you may have problems
 

SuperDave

Early-Model Mentor
Founding Member
May 3, 2000
6,361
0
0
Tacoma, WA USA
Aug 11, 2005
#4
  • Aug 11, 2005
  • #4
Also consider:

Agree with the above but would NOT overlook the possibility that the lights are not GROUNDED properly. I would check that first.
 

Loup-garou

Founding Member
Aug 11, 2001
337
0
16
New Orleans, LA
Aug 11, 2005
#5
  • Aug 11, 2005
  • #5
Rat Race said:
I put 100 watt H4 bulbs in my 67 coupe, and now every time I put the lights on , they work for about 10 minutes and then just blink on and off.

Is the bulb too high a wattage or is is something to do with the switch?
Click to expand...


It's usually the headlight switch in the dashboard. There's a circuit breaker in there that often cuts out when halogen lamps are installed. The blinking is caused by the switch cooling a bit and the circuit breaker resetting, which happens repeatedly.

Some people swap in the switch from a '69 Mustang, which has a stouter circuit breaker to accomodate the quad lamps unique to that year. However, if you're going to run overwattage H4 bulbs, skip that idea and go straight to the relays. If you don't like fooling with wiring, Painless makes an H4 Halogen adapter harness which just plugs into one of your existing headlight sockets.
 

chepsk8

Founding Member
Jan 15, 2001
2,203
3
49
Easton, PA
Aug 11, 2005
#6
  • Aug 11, 2005
  • #6
Super Dave!!!

You're back!
 

danewers

Member
Dec 26, 2004
97
0
6
Aug 11, 2005
#7
  • Aug 11, 2005
  • #7
definitely the actual headlight switch in the dash. i had the exact same problem when i got my 100watt h4's. went down to the local mustang parts house and got a new switch, havent had the problem since.
 

SuperDave

Early-Model Mentor
Founding Member
May 3, 2000
6,361
0
0
Tacoma, WA USA
Aug 11, 2005
#8
  • Aug 11, 2005
  • #8
Cheapie!

Yeah, dropped in before going on a fishing trip. Waiting for my buddy to arrive.

The Mustang is doing well and has placed in several shows this summer. Not bad for a car that was done TWENTY FIVE years ago! The "timeless wisdoms" flourish!

This forum hasn't changed much over the years. Big "go fast" ideas, no experience, no money, no skill, yahda yahda....... Good that we "vetrans" are around to temper the testosterone with injections of reality!
 

pabear89

Active Member
Apr 15, 2003
2,126
0
46
High in the Hills of So Ca with the Voices in My H
Aug 11, 2005
#9
  • Aug 11, 2005
  • #9
This forum hasn't changed much over the years. Big "go fast" ideas, no experience, no money, no skill, yahda yahda....... Good that we "vetrans" are around to temper the testosterone with injections of reality!




SD's Timeless wisdom still rocks....................

Glad to see your still out and about,
Hook a big fish for dinner,
We bears like Fish!

PB
 
R

Rat Race

New Member
Apr 3, 2005
59
0
0
New Jersey
Aug 12, 2005
#10
  • Aug 12, 2005
  • #10
Just want to get back to the subject here,...

What kind of relay do i get, and where do i get it?


How does it go in and where?

Does the painless wiring thing have a relay built in?

Thanks again, sucks having to leave shows at 8pm
 

thehueypilot

Active Member
Feb 25, 2004
1,084
0
37
Medina,Tennessee
Aug 12, 2005
#11
  • Aug 12, 2005
  • #11
The harness from Painless Wiring comes with the relay. I went to the Painless Wiring web site to get the part number for my Mustang and ordered it from Summit Racing about three years ago. I think it was around $75.
 

ericl

Member
May 20, 2004
41
1
9
Wisconsin
Aug 13, 2005
#12
  • Aug 13, 2005
  • #12
Here is a related topc

http://forums.stangnet.com/showthread.php?t=549113
 
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