When leaving work today, I noticed that when I turned my headlights on, the RPM's dropped from about 750 to below 500. Just to be on the safe side, I tested multiple times and got the same results.

The dash lights (minus the indicators thank goodness), and rear defrosters died about two weeks ago. I haven't checked the voltage or fuses yet, but I wouldn't think a pseudo-drastic loss of power would be caused by headlights being turned on (ICU)?

Huzzah for electrical problems, lol.

 

Idle Air Control Valve (IACV) should compensate for addiontal load of alternator to prevent RPM drop. Suggest cleaning IACV movement, inlet/outlet to IACV, throttle plate, and throttle bore w/ throttle body cleaner. This should improve idle compensation.

good luck

 

I am wondering if the alternator is running full out when the idle drops with the headlights on and if so why?

 

I was thinking the same thing with the IACV, throttle plate, and bore, but I did a major cleaning of all three about two or three months ago and all was fine up until the dash lights, etc. stopped working.

Could that much carbon/gunk be built up in such a short span?

 

You could have an electrical fault in the IACV and not be aware since you don't have Check Engine Light. Suggest checking for DTC's by looking at LED in the ECU to see if codes are set. Fault codes are read w/ keyswitch On. Not necessary to short service check connector.

Pull carpet back on pax side to expose housing. There are viewports near top-center of the housing to see LED flashes.

A voltage monitor (Eqqus 3721) will aid in determining if alternator is overcharging.

good luck

 

Thanks! I'll give it a shot tomorrow and see what that brings. Will post the results once I get them.

 

For a 94 Accord, to check/retrieve trouble codes, you will have to short/jump the Service Check Connector on the passenger side and count the flashes on either the Check Engine Light or D4 indicator (depending on the trouble codes, if any). There is no LED indicator on the ECU like some earlier 4th generation Accords.