Anyone else ever suffer from this? I noticed since I bought my XJR-100 the head lights will randomly "surge" or "pulse" from bright to dim and back randomly. I'm not ruling out the alt but the car only has 46k on it.

 

Check your grounds initially, but I would be more suspect of corrosion on the positive terminal on the battery....if so, replace it, you'll never get the corrosion from down inside it. I say the positive because when you apply the need for more voltage, the regulator is attempting to keep up power wants by the circuits and if the battery doesn't have a good connection, you'll see brown outs. I know your familiar with those being in N FLA....

 

I'll give it a look in the AM, wrestling that S/C all day in record heat was enough for one day!

 

Even more fun now! My rad fans keep cycling up then down every few seconds!

 

Get your alternator checked; clean the battery posts and cable; check your grounds; check the A/C switch just aft of the left side of the radiator.

Both lights or just one? Both lights, it's a common electrical issue to both . ..

Lots of possibilities: check in the stickies for the electrical tutorial.

 

So I checked the battery in the boot and while the connections were solid and clean the battery was WRONG, someone put in a battery without a vent connection (and no, it's not a ventless batt) and decided to leave the vent tube lying useless next to it and a window frame shim under the mount plate (not impressed) I'll rectify that before the weekends over. I went up front and found 3 total ground points behind both sides of the headlights. I pulled those, cleaned them, unstacked them (not a good technique) and added split ring washers top and bottom for added bite and security. For good measure I swapped the two relays to the left of the rad and pulled and reseated the a/c pressure switch. Started the car let the a/c run a bit in max and lit the lights and ran through some revs and for that little run all seemed well, time and miles will tell.