Electrical Short (No signals/guages)

[Nazgulmagefreak]

Ok, I have some kind of electrical issue. I originally thought my alternator was dying, but leaning more towards a wiring issue. Battery is good at about 12.76volts. Had alternator checked in car at autoparts store, battery checked ok and charging system problem. I was told to check all the wires and terminals. I cleaned both terminals, the positive from the alternator, and the battery ground to the chassis and engine. I cleaned the ground points to the engine and chassis. I then checked voltages, with 12.76V at battery with the car off and 12.76V. I found about 14V at the battery with the car on and the same at the alternator. I had the same auto parts store retest the alternator today, and again got good battery and apparently no output from the alternator according to their machine. The guy thinks it is not the alternator, but more likely somewhere in the wiring.

Here is what it does. I start the car and it starts normally, but sounds a little bogged down. Car drives fine and never dies, always starts on first try. Gauges remain off, along with odometer, cruise control and the SES light (which stays on all the time, due to O2 sensor prob.) is half-way dim. If I drive to 5-10 mins, usually the gauges will come on, but as soon as I press the button on the dash for cruise control, or turn on my blinker, the gauges and odometer shut off. They usually come back on a few seconds after I turn them off. I have checked EVERY fuse under dash and hood. But, headlights work both high and low, radio/clock works, brake lights work, and hazard lights work. I checked all the bulbs and not a single one is burnt out. Also, when the guages are not on, the power windows don't work.

I am lost on this one. It has lasted over a week, so I am thinking its not the alternator, cause the battery would surely be dead by now. I don't understand why the hazards work, but turn signals don't. Any help or pointers is appreciated.

[Nazgulmagefreak]

UPDATE

Got the FSM off the board and spent the day yesterday troubleshooting. I am getting 12volts at the hazard switch. I get 12 volts at the Flasher Unit. I have continuity between the Flasher unit and turn signal. I also have continuity between the Flasher unit and the hazard switch. I did check at the fuse box, but I forgot, so I am gonna retest that today. I did jump a 12V positive to the fuse box and all my gauges turned on and the indicator lights got brighter. I was thinking turn signal switch, but I tried jumping the harness to the switch and no turn signals came on. I am gonna retest everything and record it so I can post what I know for a fact. I did and visual test on the fuses along with a continuity test to make sure they were good.

[loystock]

Spec for alternator output is 14.1-14.7 VDC. Check the wiring of the alternator and the fusible link for any short circuit (crossed wire between a 'hot' and ground wire). You may also need an ammeter (clamp type or series-connected type) to check for abnormal drain from battery with engine off. In most cars, parasitic drain (from ECM, security system, etc) is @ 0.05 Amp (50 microAmps).

Since you have already checked all the fuses, unless there is a problem with the wiring, your alternator may be on the way out. It could be due to failure of an internal rectifier or voltage regulator causing lower than normal or unstable output. A failing alternator can give all sorts of problem.

Change the defective O2 sensor ASAP. Ignoring that may lead to premature failure of catalytic converter(s), very expensive. A defective O2 sensor forces the ECM to set a rich mixture which will adversely effect the 'cats.'

[Nazgulmagefreak]

I am pretty sure I found the problem. The ignition relay that powers the windows, locks, gauges, turn signals, and hazards was only putting through 1.5volts. Everything at the fuse panel that was a different ignition relay was putting out the full 12Volts. I swapped with the ignition relay above it and everything started working fine. I did notice on the power diagrams from the fsm that the same ignition relay that was bad, controls ignition signal to the alternator. Could this have been the reason that my charging system failed tests from the auto-parts store? I am going to buy a new relay today and drive it around to make sure there are no other symptoms. I am gonna get the charging system retested next week, just to make sure there isn't still a problem there. I will test the parasitic drain today after I get the relay.

Thanks for the info.

[Nazgulmagefreak]

So it Sunday and none of the parts stores that are open have the relay I need. The two other relays have matching part numbers, which are for the blower motor and accessories.

Does anyone know of any damage that would happen if I temporarily swapped in the relay from the blower motor. From the FSM, that relay turns on the blower motor and AC compressor. Please correct me if I am wrong.

[loystock]

Looks like you have identified the problem. As for the Blower Relay, the the FSM page EL-15 shows a Blower Relay with connections to Fuses #2 and #3. But if you go to the HA chapter (Heating and Air-conditioning), The blower uses no relay, just fuses #2 and #3 (HA-42) while the compressor uses the A/C Relay (HA-44). So looks like if you pull out the Blower (A/C) Relay, the blower will still work but the compressor is totally disabled.