Lights pulse on 90' TC

[Coogur]

Hello!

I am having a problem with my 90' TC, but I don't think it's anything major. The problem is that the lights in TC pulse or surge. When I say lights I am talking about virtually all of them. The headlights, tail lights, side marker lights, dome lights, the digital clock, and the thermostat control panel for the AC and heat. The radio lights along with the electronic speedometer and other things on the instrument panel are fine and do not pulse or surge at all. Sometimes the pulse is really bad and sometimes it's barely noticable. I was originally told that it is a bad ground somewhere, but am looking to get other opinions and maybe hopefully someone has come across this before or knows how to fix it. Plus if it's a bad ground, that could take forever to trace unless it can be pinpointed within a certain area.

Also does anyone know if there is a difference between the settings on an 89' and 90' TC wiper motors? I recently had a used wiper motor put on my TC and later found out that a motor for an 89' TC was used instead of one for a 90' TC. Now the wipers work tons better, but on intermitten setting they will sit up on the side of the windshield instead of going down and sitting on the bottom of the windshield when running. Is there a correction for this or should I have a 90' TC motor put on to fix it? Thank you to anyone who can possible help!

[michelq]

check charching system

[Towncar]

Re your pulsing lights:
I can't say from personal experience, but I've read many posts on this issue.

Two possibilities come up:

1) Defective regulator, unfortunately it's built into the alternator and the only meaningful test would be replacement.

2) Bad wires: This is the most talked about scanerio. Several avenues to persue with wiring as you well know. The most common problem (on this issue) with the early TC's is the actual plug that fits into the alternator from the main harness. Two problems there too. 1) The plastic plug deteriorates and eventually causes arching which can lead to Unexpected Fires. 2) The harness wires themselves corrode where they go into the terminal ends inside the plastic connector. Most people with this problem replace the wire ends and connector plug and add a fair amount or dielectric grease for protection.
The second most talked about wiring problem is the grounds. Aparently Ford wasn't very good at giving us a lifetime ground from the engine/alternator to the frame. This can be easily tested by adding a jumper cable from the alternator to the frame to see if this corrects the pulsing. If so, it would be a good idea to leave alone what Ford gave you, and add your own monster cable.

Here's two other posts on the same subject:
Another Post
Another Post

Re your wiper pausing on the glass during intermittant wiping, mine does exactly that too. If your original motor "parked" while on intermittant, that might have been designed that way for '90 but I can't say for certain.

[Coogur]

Thank you for the help. I will look into those things. The wiper thing is weird though. You said yours does the same thing. The original motor worked just fine on most the settings, but wouldn't sit up on intermitten settings like they do now. With the original motor they would sit up when you shut them off. But now with the replacement motor they do sit up on the settings, but do work on all the settings. And they do atleast go completely down like they should now though. It's weird though. Thanks for the help again!

[Towncar]

Cooqur.. it'd be great if you post back here with any changes to your pulsing lights, and what steps you went through....

[Coogur]

Ok, I will. But it may be a couple of weeks before I have time to really investigate the problem for a whole day. Till then I will be looking for virtually every possible fix for it. What you gave me Steve will be a good start and hoefully will work. But when I find what works, if anything, I will leave a reply. Have a good day all!

[Coogur]

Well, It didn't take long to find out the problem causing my pulsing lights. The first thing I checked was the alternator and BINGO! That seemed to be the mysteries problem and cause, so all I have to do is replace that and it should more than likely fix the problem. I will post a reply on whether that fixes it or not, but it should. I am about 95% sure that it will. Hopefully I will be posting good news next time! C ya!