I just bought a 94 NSX and I'm having problems getting the cigarette lighter and rear window defroster to work. I've checked the fuse box near the driver side kick panel but still can't seem to get either to work. Is there somewhere else I should look? What should I try next? Any help would be appreciated...thanks!
Rear window defroster/cig lighter problem
- Thread starter nsxheat
- Start date
There are three fuse boxes. The main relay box is under the hood on the passenger side of the car. The main fuse box is in the engine compartment, on the driver side of the car, and contains terminals for jump-starting the car. The dash fuse box is located under the left side of the dash.
The fuses/relays for the rear window defogger (fuse number 11, 40 amps) and for the cigarette lighter (fuse number 15, 20 amps) are in the main fuse box in the engine compartment.
For more information, see pages 23-47 through 23-56 in section 23 in the service manual.
The fuses/relays for the rear window defogger (fuse number 11, 40 amps) and for the cigarette lighter (fuse number 15, 20 amps) are in the main fuse box in the engine compartment.
For more information, see pages 23-47 through 23-56 in section 23 in the service manual.
No luck with the fuses. I checked the fuses in the engine compartment, all check out using the test light. Any other ideas on how to fix these problems? Any help would be appreciated, thanks!
thanks nsxtacy, I appreciate the info...
thanks lud, I'll give it a shot =)
thanks lud, I'll give it a shot =)
You can spend an awful lot of time thrashing around in the dark if you do not use a service manual for wiring diagrams and mechanical disassembly, and a multimeter for accurate ohm and voltage readings, instead of a circuit tester light. It can get very frustrating.
Troubleshooting the cigarette lighter is fairly straightforward. On page 23-222 ('92) you'll see the whole circuit. Measure the voltage on the bar at the bottom of the lighter socket, but not in the center of the bar, for 12 volts, ignition switch in 'ACC' position. Put the negative lead of the meter on the side of the socket. If the voltage is there, the lighter is probably bad. You can verify the coil in the lighter by measuring resistance in ohms from the coil's chrome ring to the outside case of the lighter. With the lighter in hand, push the knob to get the heater coil assembly to protrude far enough out to gain easy access to the chrome ring. You should read about 2 ohms. On the other hand, if there is no 12 volts, your cigarette lighter relay is probably bad. See pages 23-223 and 224. You have checked the fuses, and the same fuse #8 (under dash) feeds the stereo system, so there should be voltage up to the relay coil, while fuse #15 (engine compartment) feeds only the relay contacts A-B and through to the lighter. Measuring on connector C422 under the center console, you can verify the voltages both for the relay contacts and the relay coil (see the figure on page 23-224), using a suitable chassis ground for the negative lead of the meter. If they are both there, then the relay is probably the culprit, but wiring and contacts can sometimes be a problem.
If you have the lighter fixed before this, then great. But if not, I hope this helps.
Bill
Troubleshooting the cigarette lighter is fairly straightforward. On page 23-222 ('92) you'll see the whole circuit. Measure the voltage on the bar at the bottom of the lighter socket, but not in the center of the bar, for 12 volts, ignition switch in 'ACC' position. Put the negative lead of the meter on the side of the socket. If the voltage is there, the lighter is probably bad. You can verify the coil in the lighter by measuring resistance in ohms from the coil's chrome ring to the outside case of the lighter. With the lighter in hand, push the knob to get the heater coil assembly to protrude far enough out to gain easy access to the chrome ring. You should read about 2 ohms. On the other hand, if there is no 12 volts, your cigarette lighter relay is probably bad. See pages 23-223 and 224. You have checked the fuses, and the same fuse #8 (under dash) feeds the stereo system, so there should be voltage up to the relay coil, while fuse #15 (engine compartment) feeds only the relay contacts A-B and through to the lighter. Measuring on connector C422 under the center console, you can verify the voltages both for the relay contacts and the relay coil (see the figure on page 23-224), using a suitable chassis ground for the negative lead of the meter. If they are both there, then the relay is probably the culprit, but wiring and contacts can sometimes be a problem.
If you have the lighter fixed before this, then great. But if not, I hope this helps.
Bill
The Rear Window Defogger is a bit more involved than the Lighter.
With the Ignition Switch 'ON', does the indicator light for the Defogger switch come on when you push the switch? If so, the Integrated Control Unit is probably good, a very good sign. That also indicates the switch is good, as well as the fuses #4 and #5 in the underdash fuse box. The next thing to check is whether there is voltage going to the Defogger wire in the window. On 23-276 ('92 manual), there is a picture showing where to measure the voltage at the window wiring. No voltage at this point indicates a bad relay, or wiring associated with the relay, or wiring going to the rear window. You can carefully jump the contacts of the relay in the engine compartment fuse box. I use a short test lead with alligator clips on the ends, with paper clips partially uncurled stuck in the alligator clips. Stick the uncurled ends of the paper clips in the relay terminals. See the A-B terminals on P. 23-274. Then, re-measure the voltage at the rear window. Good voltage there points to a bad relay, assuming the indicator light came on as in the first sentence of this paragraph. You can check the relay coil as you can with any relay, using the 'Ohms' function on the multimeter, replacing the relay if the coil is open, or infinite resistance.
If everything now looks good up to the terminals on the rear window wiring, then the chances are that your window is at least partially defrosting. If a partial defrost pattern is indicated, then check each wire in the window for a broken conductor as shown on 23-276.
Going back to the beginning, assume that the indicator light did not come on, that the fuses are good, and that all the other functions of the Integrated Control Unit are working. This strongly points to a bad Defogger Switch, or a partially failed ICU.
Direct testing or replacement of either of these items gets somewhat involved. See pages 23-156 and 159, also pages 23-273 and 275. I hope it doesn't go that far. I have been into the switch cluster, which is bad enough, but not the ICU.
Let me know if this helps. Good luck.
Bill
With the Ignition Switch 'ON', does the indicator light for the Defogger switch come on when you push the switch? If so, the Integrated Control Unit is probably good, a very good sign. That also indicates the switch is good, as well as the fuses #4 and #5 in the underdash fuse box. The next thing to check is whether there is voltage going to the Defogger wire in the window. On 23-276 ('92 manual), there is a picture showing where to measure the voltage at the window wiring. No voltage at this point indicates a bad relay, or wiring associated with the relay, or wiring going to the rear window. You can carefully jump the contacts of the relay in the engine compartment fuse box. I use a short test lead with alligator clips on the ends, with paper clips partially uncurled stuck in the alligator clips. Stick the uncurled ends of the paper clips in the relay terminals. See the A-B terminals on P. 23-274. Then, re-measure the voltage at the rear window. Good voltage there points to a bad relay, assuming the indicator light came on as in the first sentence of this paragraph. You can check the relay coil as you can with any relay, using the 'Ohms' function on the multimeter, replacing the relay if the coil is open, or infinite resistance.
If everything now looks good up to the terminals on the rear window wiring, then the chances are that your window is at least partially defrosting. If a partial defrost pattern is indicated, then check each wire in the window for a broken conductor as shown on 23-276.
Going back to the beginning, assume that the indicator light did not come on, that the fuses are good, and that all the other functions of the Integrated Control Unit are working. This strongly points to a bad Defogger Switch, or a partially failed ICU.
Direct testing or replacement of either of these items gets somewhat involved. See pages 23-156 and 159, also pages 23-273 and 275. I hope it doesn't go that far. I have been into the switch cluster, which is bad enough, but not the ICU.
Let me know if this helps. Good luck.
Bill
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