Headlights - both hi and low beam on at the same time

[Steveend-1968]

My hi-beam works but when I switch to low beam both the hi & low beam lights up. It seems like the multi function switch.

Any ideas?

 

[billison]

I’d start by listing what car you have.

But shooting from the hip, I agree

 

[Steveend-1968]

Oh ya, '93 mustang

 

[JD1964]

In the older cars with 4 headlights, when you switch the highbeams on, all 4 lights stay lit. Shouldn't it be the same on newer style? Both elements stay lit?

 

[Steveend-1968]

Yes and it's like they're in series because the light level is like a candle on a dark snowy night - DIM....

 

[Steveend-1968]

I found the problem. It's my son's car and he bought some aftermarket headlights which I helped him install, what I didn't know was that it came with bulbs but they were 9007's not the stock 9004's for that year. The pin out is different so on low beam the power was going through the low & high beam filaments. Since the bases are different we're splicing on another set of plugs wired for 9007 bulbs.

 

[jrichker]

I found the problem. It's my son's car and he bought some aftermarket headlights which I helped him install, what I didn't know was that it came with bulbs but they were 9007's not the stock 9004's for that year. The pin out is different so on low beam the power was going through the low & high beam filaments. Since the bases are different we're splicing on another set of plugs wired for 9007 bulbs.

The same thing happens with the headlight ground is broken or disconnected...

 

[Steveend-1968]

Good to know thanks for that, we'll double check ours.

 

[Steveend-1968]

Wait, I did check it already.