Ok, you all have probably heard of this one before. I just got a 87 Mustang GT and the lights are pulsing when I drive. When I come to a stop, the pulsing pretty much stops but it is still there slightly. Any ideas as to how to fix this?

 

A new voltage regulator.

 

I have already put a new alternator on the car and when it still was pulsing, I tried putting a seconf new voltage regulator on there. Any other suggestions??

 

Just a crazy question? do you have a system in the car?

 

Sorry, I don't look at any question as being crazy. Of course being a novice at cars, I am somewhat biased. To answer your question, no, there is no system in the car yet. The stock radio is there but the speaker wires have been cut as there is no sound coming from them. The radio powers up and the eq lights dance as if getting signal, but that is a problem that I do know something about so I can handle that one. One clarification though, when I say lights pulse, ALL lights pulse. Including the time display on the radio, the dash lights, etc.

 

OK, sounds like more of a ground issue, I would begin by checking all of your grounds, Ford has a bad history of weak grounds, inluding the brainfart of trying to ground through the computer on the eec-iv's. Also check for a dash voltage regulator, usually behind the cluster, dont remember what year they quit using them as external pieces. It would look like a circuit breaker(grayish metal box) with a nine-volt style hookup, plugs directly on the back of the cluster if memory serves me right. just a few ideas, cant do much more with out the car in front of me.

 

Thanks for the info. I did check the grounds and they seemed to be fine. I even took sandpaper and made sure they were making good contact. The ground from the battery did not look very good at all so I cleaned it all up and now it is making a good connection.The dash voltage regulator I have not checked for. I will look for that next. It is really not that big of a deal. Just more of an annoyance at this point but I am determined to get rid of it!! I have also noticed that the charge indicator needle on the dash jumps with the pulsing. This problem only occurs when the RPM's get above idle. You are always welcome to take a road trip and come out to take a look at it!! Thanks again. Will post when I find out if it has that regulator behind the dash.

 

I would remove the Alt and Battery and have them bench tested. Have you recently added anything new that runs off of electricity?

 

Also one more thing to check, there is only 1 or 2 wires that feed main power to the dash, I dont have a diagram in front of me right now as im at work, but i would check the voltage on that(you would need an old style analog meter) and watch to see if it pulses with the flash, if it is you are getting a power surge from somwhere in the system. I noticed you said that you have replaced the alternator already. If the stator rings are not turned true ( Completely flat) it will cause the brushes to bounce and make intermittant contact and would be more noticable at higher rpm's and the rebound effect is much higher. I have seen some that were so bad that it would just quit charging until you full fielded the unit. It happens alot with the off-shore and backyard remans that most parts stores are carrying these days.

 

I will be sure and check those two wires as well. As far as the Alternator, I had everything replaced new. The guy that I have that does the work is very trust worthy. He said that the old alternator was completely shot so he put a brand new one in for me. He noticed the pulsing was still happening so he took it off and replaced the voltage regulator and stator rings as well and still the pulsing remained. He was perplexed as I am and is very curious as to why this is happening. Thanks.