flash to pass works headlights dont

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spitfire
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flash to pass works headlights dont

Post by spitfire » Sat Mar 16, 2013 4:56 pm

So here is the thing.

Late one night in January I was driving home and suddenly the headlights went out. The switches were broken so trying to go to brights wasn't going to happen.

A few months later I get new switches, including the headlight switch. Now Flash to pass works, which tells me the lights are good, and that the ground is good. The indicator lamp comes on in the dash as well.

However the headlights still do not work. All other lights on the car work properly. When I switch to brights I also do not get an indicator lamp.

I don't know where to look next and I really need to get these lights working by the end of this weekend.

Please help. Or if anyone is in Riverside, come on over and help troubleshoot. Because I just don't know where to look.

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kiwimark
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Re: flash to pass works headlights dont

Post by kiwimark » Sun Mar 17, 2013 7:01 pm

Hi
I had this exact problem on my MG BGT and it was the column stalk switch. The lights are routed through this for low/high beam control and flash to pass. I am now on my 4th replacement switch in 2 years as they seem to last 6mnths and then break as the plastic is so brittle. I would look to an oe one, either nos or second hand rather than a new part as they are crap. To test the switch, unplug it from the loom, find what wires are the lights and test continuity for high and low beams.

Hope this helps
Mark

spitfire
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Re: flash to pass works headlights dont

Post by spitfire » Sun Mar 17, 2013 9:13 pm

I just checked for current on the connector and there was no current on any connector with the lights on in dim or high. Being alone I wasn't able to do the check with the flash to pass.

I also checked the blue/white wire. Again those are working fine. I cleaned all the connectors at the front of the car.

I am thinking that the issue may be at the sub harness under the dash. I also get random shorts where the whole dash doesn't work, unless I jiggle the harnesses.

would this be the sub harness or the full harness that I would need to replace? Also would that require taking the whole dash off?

wellwoodautorestoration
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Re: flash to pass works headlights dont

Post by wellwoodautorestoration » Mon Mar 18, 2013 8:28 am

Check your dimmer switch on the floor before you tear the signal switch out. All headlamp power runs through this and connections can get bad or the switch fail. Check for power into and out of the switch in high and low beam positions.
Cheers, Dave
Wellwood Auto Restoration

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Re: flash to pass works headlights dont

Post by Fifty Six MGA » Mon Mar 18, 2013 11:50 am

I'd put in a second vote for checking the dimmer switch. That was one of the issues I had on my car that turned into a simple fix once I found it. Finding it took weeks of frustration.
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spitfire
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Re: flash to pass works headlights dont

Post by spitfire » Mon Mar 18, 2013 2:41 pm

I thought the dimmer switch was on the signal switch. I had to replace that anyway since it was completely broken. So where is the dimmer switch located exactly on the B?

wellwoodautorestoration
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Re: flash to pass works headlights dont

Post by wellwoodautorestoration » Mon Mar 18, 2013 4:45 pm

On a 76 MGB the dimmer switch is on the stalk so no floor switch. I though"Spitfire"!
Check your connections under the dash where the signal switch bundle joins the harness.
Cheers, Dave

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