I have one headlamp that is flickering. Have take both units out and tried them in each headlight. Same problem. I have a alternator that is screaming like anything. Could this be the problem?

 

yup a bad alternator could cause that

it might not be charging the system correctly

 

I put the wrong thing in, I meant to say relay not alternator. The relay is screaming

 

what relay are you talking about ?

also it would help to tell us what your driving
Pics are great also

 

blazer 2002, right hand drive.

there are two relays at the back by the wiper hosing for the headlights. When you put the lights on full beam, it screams like hell. Only one headlight was flickering.

 

Relay has an issue (though I'm unfamiliar with relays on a firewall). But either could be a ground issue. Does the flickering happen more over bumps or when the engine is reved? If so that sounds like a ground or a connection issue. See what could move as the engine turns as it gets reved. The engine ground at the rear to the firewall (PS LHD vehicles). Might even be as simple as a bad connection in that connection housing. You said you swapped headlights & the same side has the same issue so - what about the connections? Tough to test them, this side of replacing them (not a big coin issue really) but it's the same issue with that side, we know that - right?!
Use that thinking to narrow down the possibilities. <--- whats specific with THIS side.

Just my thoughts, connection issues, be it a ground - maybe or a molex/head light connection issue. Worse case scenerio is a bad BCM IMO - $40 at a wrecker.

Check the grounds just because & look for water, corrosion in the connector to the troublesom light. If not that trace it back.

 

I learned something today. I didn't know relays could scream.