This I find very odd. Here's the rundown. Newly rebuilt motor, new alternator, new battery cables. Battery terminals cleaned. Idle at 850-900. When I put the heater on the idle will change about 100 rpm. Is this normal? I think the headlights dim as well when I do this. Also, I don't think its a water pump issue since I have a problem with the heater control valve and that's open full time until I fix the cable that runs to it.

I am thinking maybe the blower motor is worn out drawing more power than it should be causing more of a strain on the alternator resulting in a lower Engine RPM?

This I believe did this before the rebuild as well.

 

try testing the blower motor with a ohm meter to see how much juice it draws. I think the specs are in the factory service manual

 

Mine does the same thing.

From what I have read the big 3 upgrade will fix this...

 

gonna have to help me out here and explain a bit, still kinda a newbie at these toyotas.


somehow I wound up with a parallel thread and the blower resistor came to mind as well. ( I guess I am a reposter too haha )

 

It is a twofold problem.

One, the alternator is so weak that it cannot support many accessories. Two, the cables are fairly small to start. This is why everyone suggests the big 3 upgrade. A friend I helped with his 92 4Runner did the Big 3, and installed an upgraded alternator, and never had this problem again. Even after running a TON of electrical accessories.

 

2 gauge battery cables and a brand new alternator. I think its the blower motor drawing too much. I will get a chance to look at this tommorow and post up, if I don't freeze to death before then lol

 

Try upgrading your alternator to a bigger amp.

 

don't really have the funds for that just yet, and the way I look at it, it didn't do this when it was new, why should it do it now. The only extra accessory I have on the truck is the crappy aux lights.

 

Live with it for now. Keep your eye on it. Upgrade your alt when funds premit or mybe a blower motor from a boneyard...