98 cobra alternator issues

[98fastcobra]

hey everyone so I kind of have a problem... so a couple weeks ago I've been having issues with my alternator/guage cluster... lately on my dash the voltage reads low and the lights are dimmer than normal and heat isn't blowing as hard... I have replaced both the battery and alternator and it still reads low sometimes .the funny thing about it is that sometimes it would read normal where it should be ( no dim lights heater blows normally) and everything is fine and then the next day it will read low again with the same dim light and heat problem. took it to autozone twice and the first time the battery and alternator was in good shape but then the next time I went up there the alternator was not showing any indication of working and wasn't registering on their device but then the next day the alternator and everything is fine... what would cause this . it seems this issue randomly works/acts up when it wants to... I don't want to randomly start buying new parts to hopefully fix the problem,.

 

[98 svt]

Voltage regulator?
Or maybe a loose ground?

 

[98fastcobra]

I will look into those... I'm assuming the ground connection is under the car....

 

[98fastcobra]

also is it possible for an alternator that I bought new a few weeks ago have a bad voltage regulator

 

[hotcobra03]

Chilton Library

Scroll down to resource link to enter

There are wiring diagrams and pictures of locations

if you use the search bar in link you have to click go on that bar.

site is timed. If you pause to long you need to start over from main link in


When I had issue like this
Running a jumper ground from battery to engine showed volt change at battery.

ground from battery to radiator support was for in car power

this burned up on mine on the inside of casing where you didn’t see it.
Replaced with a large cable from Walmart battery section

03 still has issues with lights dimming.


There is a big 3 wire upgrade
Try a search on here

 

[DSG2003Mach1]

also is it possible for an alternator that I bought new a few weeks ago have a bad voltage regulator

anything can be bad out of the box. Electronics really seem to either fail super quickly or last a decent while. if it's an autozone alternator I'd almost bet on it, anything like that I've ever bought there has been shit

 

[Tillerman77]

anything can be bad out of the box. Electronics really seem to either fail super quickly or last a decent while. if it's an autozone alternator I'd almost bet on it, anything like that I've ever bought there has been shit

+1 on remans in general. I had 2 bad Ford reman alternators in my 97 Cobra over 2 years. 3rd one is still working. Also agree to check the several ground connections in the engine bay. A couple of mine were loose.

 

[98fastcobra]

well the alternator I bought a few weeks ago was an ac delco one from Rock Auto it was 160 for it ..... I will check the ground connections to see if they are ok..

 

[DSG2003Mach1]

well the alternator I bought a few weeks ago was an ac delco one from Rock Auto it was 160 for it ..... I will check the ground connections to see if they are ok..

I cant remember if you can see voltage output through the digital cluster when put into engineering mode or whatever but I would also seriously consider getting something to plug into the OBD2 port and see the actual voltage instead of the dummy light on the dash. If you do monitor via OBD2 I would still use a volt meter and check voltage at the battery to see what the variance is between the two, the OBD2 always reads lower than actual output but its usually by a consistent amount (ie 13 volts at battery and 12.7 on gauge)

 

[98fastcobra]

I have an ultragauge that I use through the obd2 port for my readouts I will add battery voltage to the on screen display for the car... but I will see on trying out the voltage regulator... all of this just happened out of the blue so it's odd because I've owned this car for 3 years and never had charging/voltage issues unitl one day I was driving and the car had super dim lights and eventually things were shutting off the the car died while I was driving..

 

[98fastcobra]

I have an ultragauge that I use through the obd2 port for my readouts I will add battery voltage to the on screen display for the car... but I will see on trying out the voltage regulator... all of this just happened out of the blue so it's odd because I've owned this car for 3 years and never had charging/voltage issues unitl one day I was driving and the car had super dim lights and eventually things were shutting off the the car died while I was driving..

 

[hotcobra03]

I use my radar detector on volt mode.

I used orielys for lifetime warranty and easy to get when I need


Another area that will get you.
Battery terminals

I have universal type. Clamp over cable.

these you really need to keep clean underneath clamp

some will have paint all over inside which was a mistake

some come painted but not where cable gets clamped

 

[98fastcobra]

ok so I'm going to start with the positive terminal battery cable.. had corrosion on it so I cleaned it off and let's see if this does the trick..

 

[98fastcobra]

so I tried cleaning the terminals and check connections and they all seem right and I still have the issue.... I'm guessing my "new" alternator is faulty....

 

[Tillerman77]

That had been my experience, as noted above. The warranty on the Ford reman alternator was 2 years, so the next time it goes out I am buying a new one, not a reman.

 

[hotcobra03]

Are you still reading volts from inside car?

if so. You need to start at battery with testing and post up voltage numbers.

Inside of car uses a different ground. To body
G203

ground from battery to radiator support need to be looked at.

the large ground to motor does starter and engine

with meter at battery terminals
You may see 14 volts than ground to body and see 13 or less

this is what I was seeing before ground upgraded wire from battery to body
Now 14 in car

any parts store will bench check your alternator for free

 

[98fastcobra]

so I took the alternator off and had it bench tested by three different AutoZone's and all of them have said that the alternator is fine... and I know for a fact the battery is fine as well because I bought that brand new two weeks ago and also had them bench test that

 

[DSG2003Mach1]

so I took the alternator off and had it bench tested by three different AutoZone's and all of them have said that the alternator is fine... and I know for a fact the battery is fine as well because I bought that brand new two weeks ago and also had them bench test that

their bench test doesnt mean shit, especially with an intermittent issue. My Lightning ate 3 starters from autozone, all of which tested fine. They would all hang on the flywheel after a couple of starts. I went and bought a Car Quest started and never had another issue, still had to argue with autozone to get my money back even after telling them I'd been running Car Quest for a month without issue.

 

[98fastcobra]

dsg2003mach 1 your absolutely right.. I did further test and it was indeed a faulty/quirky voltage regulator within the alternator.... advance auto parts said everything checked out.... I'm glad I was able to finally... so my next question should I just replace the voltage regulator or just buy a new alternator all together

 

[98 svt]

dsg2003mach 1 your absolutely right.. I did further test and it was indeed a faulty/quirky voltage regulator within the alternator.... advance auto parts said everything checked out.... I'm glad I was able to finally... so my next question should I just replace the voltage regulator or just buy a new alternator all together

Lol I said it was the voltage regulator on post #2