Electrical Problems?

[dwsykes]

When I turn my fan on in my 88 Ranger it sucks alot of electricity from the headlights/interior lights and you can hear the engine change in RPM. Does this make any sense? Do I need a new alternator or fan?

 

[Earl43P]

Clean your grounds.

Might also have corroding cables or battery terminals.

I'd check the voltage drop at power points and use different grounds to figure that out.

Especially true if it does this at operating rpm, not just at idle. You have no reason to suspect the alternator yet. This screams bad ground or cable to me.

You can also use a single jumper cable, if you don't have a meter. Connect from the
-Bat to the engine block, try it. Connect again to the chassis (bare metal), try it. Connect again to the frame, try it. Then go to B+ and connect to the alternator + post(big red wire), try it. Then B+ to the solenoid (follow the cable from the battery so you don't crank the starter if you use the wrong post on the solenoid). You're basically just duplicating an existing power or ground path. If it improves with a jumper, that run of cable, ground, etc. is bad.

Check your alternator belt too.

 

[MAKG]

By the fan, you mean the blower, right?

Check the current draw with a clamp-on ammeter. Dying blowers draw excessive current. I believe it's supposed to be 10A on high. Alternatively, pull the heater control head out and see if the blower switch is starting to melt (very common).

 

[kena]

Look under the hood (passenger side) and remove the blower motor. Reach in the hole and extract all the pine needles and leaves that have accumulated over the years. Your blower motor will thank you.

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