calvink

Installed an aftermarket radio, and it worked, driving around for 2 days. On the highway, started getting sparks, popping, and smoking from the radio area. Started to pull over, put on the hazard lights and the car stopped mid-drive.

Immediately after being towed home, tested the fuses. Fuse 44 (PGM-FI) and 47 (Back Up (Radio)) were blown. Tried replacing the fuses. Fuse 47 will blow immediately upon replacement. Tried putting a 30A fuse in that slot out of curiosity and it didn't blow. Fuse 44 will blow when trying to start.

Replaced the battery because it needed to be replaced anyway.

Also replaced a possible bad ground from the radio connector.

Some other things that don't work now: tail lights, brake lights, front and back turn signals, and license plate lights.

Tested the fuel pump on its own and it isn't the source of the short for fuse 44.

No real ideas why fuse 47 keeps blowing.

Currently the dash is taken apart, A/C, hazard lights switch, and radio unplugged.

Former User

Fuse 47 supplies constant voltage to the radio. Fix the bad radio wiring job, and hope you didn't blow the ECU.

Does unplugging ECU connector B prevent either fuse 47 or 44 from blowing?

fcm

Ditto the above^^^ remove the radio then replace fuses, but NEVER with a bigger fuse.

If everything works reinstall/wire radio properly. 94

calvink

Thanks! Taking out that ECU connector did stop the fuses from blowing. Does this mean that the ECU is bad and needs to be replaced?

Former User

Sounds like you fried the ECU. Fix all wires before installing a replacement or you'll be right back where you are now.

calvink

So far all the wires we've tested seem to be fine, themselves (aside from the ground off of the radio connector which has been replaced). Are there any other wires in particular we should watch out for?

Sharpie14l

You should specifically be looking at anything involved in the radio wiring area. It could've cooked any of it

calvink

A few new pieces of informations. We wanted to confirm that the fuses would blow again if we reconnected the ECU connector.

First test: with the battery terminals disconnected and the fuses in, replugged ECU connector B. Then we reconnected the battery terminals for about ten seconds and disconnected them. Checked to see if fuse 47 blew. It didn't.

Second test: Reconnected the battery terminals and tried starting. Had a loose battery connection, so nothing new here.

Third test: Pulled out the fuel pump relay after the last test and left it out for this one. Tried starting the car. Nothing blew.

Fourth test: Reconnected the relay. Tried starting the car. Only 44 blew.

So somehow something happened and now fuse 47 no longer blows continuously. When we try starting the car, it turn over but it won't start. We tested the fuel pump relay and it is working properly. Is the ECU still the most likely problem? Could there be something with the fuel pump itself?

calvink

We're going to replace the ECU and redo connector B. We opened it up and found some damage to it. We are planning on going to the scrapyard to try to find a new one. The part number on ours is 37820-P2E-A92 - do we need to look for this exact model, or are there others that would work too?

Former User

Buy a 99-00 P2E that matches your transmission.

calvink

Replaced the ECU with one from the junkyard and replaced a somewhat worn ground from the front of the engine to the frame...and the car starts now. (Thank you!) We were able to drive it around. Some problems still remain with the lights. Even after reconnecting the hazard light switch, the turn signals don't work. We could put on the left signal and the left rear would light up but not blink, right one wouldn't work at all. We checked and the right rear bulb was burnt out so we replaced both. Now the right one will light up (still won't blink) and the left won't. Front turn signals don't light up at all. The brake lights haven't worked ever since the car broke down and still don't work. No blown fuses. Headlights and high beams work. Haven't tested the flasher yet. Wondering if there is some (other) obvious place to start? Thanks!

Former User

Test the brake light fuse #52.

https://honda-tech.com/forums/honda-...fuses-3079359/

calvink

We checked engine codes by jumping the wires and got the following four codes:
20, 41, 65, 70. Tested all fuses under hood and under dash. All under hood fuses are good, including 52. Horn has always worked. Under dash fuses 23(SRS) and 15(Alternator SP sensor) were blown. Replaced both and 15 is good, 23 keeps blowing. Under hood fuses 4, 5, 10, 11 (I don't have power windows), 21, 22, 30, 31, 32 all NOT receiving nearly any voltage from either test tab. The D4 drive light on the instrument panel does not light up anymore when the car is running and in Park. However, when checking the engine light codes, this light blinked in a code-like pattern: (1)Short (1)Long (6)Short blinks. Does that mean anything?

The SRS system and battery were never disabled/disconneced during the radio installation that seemed to trigger all of this. It is possible that the SRS connections (under steering wheel and on left side behind glove box were not reconnected tightly when put back together, and could've shorted from that. I'm guessing we screwed up somewhere with disconnecting and reconnecting them. Any thoughts?

The strange thing about the lights is that the headlights and brights DO work, but the related fuses are not getting voltage. and although Fuse 32 is not getting voltage, the licence lights DO work but the tail lights do not. The instrument lights DO work, although fuse 30 is not getting voltage. And even though the turn signals and brake lights do NOT work, the fuses are okay. Hazard lights do NOT work now.

What do you recommend next? Thank you!

calvink

Also, Fuse 31 not getting much of any voltage but car starts and things beep when keys are in ignition if door is open, etc.

Former User

Check whether battery voltage reaches Grn/Wht wire of each brake light bulb socket. FYI - The brake light bulbs should have two filaments as the bulb also serves as a taillight.

Fuse 31 only gets voltage with key in ON(III).

Fuses 4, 5, 21, 22, and 32 only get voltage with light switch on.

Fuses 10 and 11 --> Does your CX have power windows?

If you unplug the SRS unit, does fuse 23 still blow?

Post video of D4 blinking code.

calvink

We ended up just finding that the flasher relay and a bunch of bulbs needed to be replaced. It ran for a few days, but then while driving we started to smell rotten egg-like fumes. Opened up the hood and the battery was hot and venting steam/smoke. Looked up the problem, and it said the alternator was probably overcharging the battery and that it shouldn't be driven, so we had it towed back home. Just did a few tests of the alternator starting the car just for brief periods of time. Sure enough, battery voltage was 12.44V disconnected (after sitting for 3 weeks), 12.68V connected, and 18.8V when the car is running. Also, with all electronics turned on (except the radio which isn't installed) we're getting high voltage drops from the positive and negative sides of the alternator to the respective battery terminals (.87V on the negative side, .5V on the positive). Is it more likely that 1) the ECU is sending the wrong signals to the voltage regulator 2) the voltage regulator is bad and we should replace the alternator or 3) still a bad ground somewhere. Or several/none of the above.. Where should we go from here?

One more thing - the SRS fuse keeps blowing Fuse 23 - I think this is because we did not properly disconnect the airbags at one point when we were connected and disconnecting the battery a million times.

calvink

We also have access to a cable tracer, which may be able to help us.

K20A3F00L

Holy hell! Sounds like a lot of **** going on, hope you get it figured out soon!

oneheadlight

This is simple. The voltage regulator is bad on the alternator. Either replace the alternator or the voltage regulator (if you want to take it apart). Most people just replace the entire alternator, since the voltage regulator is inside. The ECU does not tell the alternator what voltage to give, not over 15volts. you're reading 18v! Yup it's bad, that's why it's frying everything! Way too high.. so simple, replace the alternator, should fix everything else.

mk378

Correct, you have to fix the over-volt first, which burned out the bulbs and other stuff.

Power from fuse 15 to the yellow-black wire on the alternator is important for proper alternator operation, but a failure there seems to always lead to varying and under-voltage not over. But do turn key on (engine not running) and confirm you have voltage on that wire.

Smoke coming out suggests that the harness may be internally melted and some wires fused together.