alternator warning light...Loose fan belt(?)

[on-ramp]

Recently rebuilt my alternator on 70T but the light still comes on at idle but goes out at higher RPMS.

I suspect my fan belt is loose. where do I place the shims to tighten it? thanks.

[RoninLB]

how much fan belt play ?

[on-ramp]

i dont know how much play, have to check tomorrow. i just need to look at the easy things first to sucessfully diagnose this problem

[RoninLB]

the red lite warning at idle was pretty routine for those early 911s. there are solutions after you confirm a good charging system

[Early_S_Man]

[rick2]

I had the same trouble, seemed like the belt was fairly tight and had gone to a newer alternator version with internal regulator.
Result: Added another shim (6) shims total. Pain to get on but did the trick.
I would clean up the ground bolt and the copper leads on the body by the battery. That cured a problem I had that I was blamming on the switch

[RoninLB]

Originally posted by rick2
That cured a problem I had that I was blamming on the switch

I changed a decent ignition sw at 100k miles when I did the headlight switches game to help prevent this sort of BS from driving me nuts.

[on-ramp]

Originally posted by rick2
I had the same trouble, seemed like the belt was fairly tight and had gone to a newer alternator version with internal regulator.
Result: Added another shim (6) shims total. Pain to get on but did the trick.
I would clean up the ground bolt and the copper leads on the body by the battery. That cured a problem I had that I was blamming on the switch

Rick,

how did you arrange the 6 shims? some could go on the inside , some on the outside. please explain

[RoninLB]

Originally posted by on-ramp


how did you arrange the 6 shims?
please explain

101 Projects , p21

[vash]

i think if your belt was loose, your light would come on occasionally at above idle engine speeds. but it wouldnt hurt as the first check.