My battery light in my Expedition will come on when RPMs get around or higher than 4000, I also notice that the lights and dash dim. I have googled it and found that some people say it could be the alternator, I have replaced the battery, The truck drives well under 4000 with no light, I run into this when towing and the rpms get high, Well today the light came on and stayed on and I noticed the volt meter on the dash was at say half of what it normally is, I was going to put a meter on the battery when I got to work but it cleared before then.

Any thoughts,

I just want to see if anyone else has had this issue.

Thanks

-Mike

alternator -

when the light comes on the charging feild is turned off, so no output. after time and age the alternator max output will lower, so at 4000rpm the demand is more than the output and the alt turns off -

get a good alt, not an autozone - autolite - kragen - etc. get the ford or napa - and if its an option get the larger amp unit

The alternators I have seen are 130 amp, Thanks I will check with Napa.

When looking to replace the alternator there are 130 amp ones for around $150 and 200 amp ones for around $350. Is the extra 70 amps worth it? This is my DD and tow rig. It is bone stock.

Bump for the day crowd

Fixed,

I picked up a 130 amp alternator today, Just finished installing it, Runs and Charging perfect, No battery light at any RPM.


Thanks For the Help

Fixed,

I picked up a 130 amp alternator today, Just finished installing it, Runs and Charging perfect, No battery light at any RPM.


Thanks For the Help

you only need the extra 70 amps with upgrades over factory - aftermarket lights, amp/subs, electric fans. otherwise, factory works fine. On all of my vehicles when the alternator goes out, i always go for the bigger one if there is an option. if not, there is nothing wrong with the factory amps. :grinpimp: glad to see you got it worked out. plus, 130 is huge anyway for most alternators.

damn - im late -

but you can install a HD - aka police or ambulance build alternator - napa has them too - and most of them start at 180 - 250 amp

i have a ambulance alt on my 95 F250 with a 351 - it was a compleate bolt on - i looks the same, but had a little heat sink on the rear ( though i did install a bigger charge cable - not req though ) - the old one was 105 amp - this one was 220 amp rated - and tested at 258 amps ( they should include the testing papers in the box )

it wasnt listed for my rig - but i grabbed the book and looked at the application and pic guide - it was listed for a 95 f350 5.8 ambulance package. they didnt have it in stock, but it was 1 day out - and only 80.00 more than the std. alt


my truggy is getting the 210 amp svt had on his green beast, from a efi 460 ambulance