no beam/ high beam!

[XJRpilot]

no beam/ high beam!

i just put a pair of new h4 headlamps in the b last weekend. worked great on low and high beam.
yesterday the highs worked, but the lows didnt.
i got the trusty meter, which told me the highs are getting current but the lows are not at the 3 female connecter at the headlamp. geez, i knew that already. is there a relay or in-line fuse for the low beams that i cant find? no mention of any in the bentley manual. all the fuses in the engine bay are ok. how about the stalk/switch that changes low to high? could that be the culprit?

 

[Tom]

Re: no beam/ high beam!

What year is your car?

My guess would be the high beam/low beam on the stalk if it is an early to mid seventies car. The contacts work on the springiness of a pair of copper contacts and over time they harden and becomeless flexible eventually the contact fails.

If it is this it is an easy changeout but the unit is not cheap.

I've had to change out this unit twice in the 17 years I've had my 1970 MGB.

My 1968 MGC still has a floor mounted dipswitch which is somewhat more robust than the column offering (if you can put up with that sort of thing)

regards

Tom Edge

 

[Bruce74B]

Re: no beam/ high beam!

I agree with Tom...it is probably the stalk switch...and easy diagnonsis to make...remove the cowling and jump the switch from the purple wire to the low beam side and see if they light then...careful to avoid the ground or you will short them all out and answer your question about where it is fused...before the switch. Chances are the low beams will light and you will know that it is the switch causing the problem.

If you are anything like me, you probably wore it out playing with your new lights.

It is a delicate switch and might be able to be cleaned with a small piece of wet and dry and work for a while, but replacement is an eventuality, my friend.

Bruce

 

[SilentUnicorn]

Re: no beam/ high beam!

i had the same trouble the other day....turned out i had a bad connection on the left side front wiring harness, not at the lights but where the harness junctin is for the running and turn on the left front....one of the 4 way connectors was bad...be sure to check both...hot and ground

 

[XJRpilot]

Re: no beam/ high beam!

wow, talk about similarities in british electrics! i removed the cowl and checked the switch, turned out ok, i was getting 12 v on both the high and low beams. checked voltage at the headlamps: nothing. turned out to be the connection under the left front dash. cleaned the male pins and females and reconnected the harness plug and all was fine. a touch of the lucas flu i guess. saved about 60 bucks by not buying a new switch, god i love my b!

 

[Guest]

Re: no beam/ high beam!

Last year I had to replace the stalk on my 74, as I also had high beams but no low beam capability, and low and behold I soon had both working properly. I wasn't able to find any fuses between the lights and the switch and spent a lot of time trouble shooting the problem (I didn't know this forum existed). Talk about driving in the dark!!! I did however try to repair the switch in the console stalk, but that only lasted a couple of hours. I determined it best to just buy the replacement part.

 

[MGFever]

Re: no beam/ high beam!

I had a similar problem on my Midget. Ended up replacing the stalk too. On my GT, when I upgraded the lamps to halogens, I decided to upgrade the circuit as well. The sitches as described here are very light duty. With amperage and age they give out. The fix is to use relays and it's really not a tough or expensive upgrade. Here is a URL that I got off Muenchausens site. Excellent article.
https://lighting.mbz.org/tech/relays/relays.html