INFO:
1990 HONDA ACCORD
4CYL.
AUTOMATIC TRANSMISSION

Hello forum! Just wanted to ask for some help to find out why my 1990 accord keeps frying alternators. for background, the first one lasted about a year, the second one 3 miles and the third about 20 minutes of idling. I cant believe all these could be bad.

Being suspicious, I disconnected the wiring harness from the Electronic Load Detector and there was no short among the 3 terminals on the ELD itself. However, at the wiring harness which connects to the ELD, the BLACK/YELLOW wire is shorted to the ground (BLACK) wire. so I referred to a Haynes manual and found that the black/yellow wire can be traced back to the following components:

BYPASS SOLENOID
EMISSION CONTROL BOX
ENGINE MOUNT CONTROL UNIT
ALTERNATOR
INTAKE AIR CONTROL SOLENOID

I disconnected the emission control box and the alternator to see if the short would go away and it didn't. I didn't test the other 3 because I cant find them.

Now what I want to ask is:
1) can a short on this wire or one of these components cause my alternator to fail?

2) Could someone please tell me the locations of the bypass solenoid, engine mount control unit, and intake air solenoid? I want to disconnect these components and recheck for a short at these as well.

Thank you all for your help in advance!

 

1. First check the amperage of Fuse No. 2 in the under-dash fuse box, it should only be 15A. If a higher amperage fuse was used instead, you risk the fuse not providing the intended protection and other components getting damaged when there is a short, etc.

2. That fuse and the Blk/Yel (IG) wire supplies the ignition input that turns on the alternator/regulator assembly.

3. The regulator in the alternator is probably what is getting damaged.

4. What trim level is your Accord? Not all models have the bypass solenoid and/or the Intake Air Control Solenoid Valve.

5. The Engine Mount Control Solenoid Valve is located at the center rear of the engine compartment (firewall).

 

Thanks Red Bull, I'll check the fuse out. Also my trim level is an X. Lastly the engine mount control solenoid it must be the one with the vacuum hose connected to both the intake manifold and the engine mount in the rear correct?

 

Sorry for the Misprint
the trim level is an e x

 

The EX does not have a bypass solenoid.

I will post photos of the components later today, I have things to take of this morning.

 

Thanks Red Bull and I'll let you know what I find.

 

Red Bull just to give you an update there is a 15 amp fuse at the number 2 spot. I also checked under the hood and found the intake air control solenoid and the engine mount control unit and disconnected both and still had the short on the black yellow wire and the ground wire.

 

I will take a look at the circuit diagrams then to see if there are other areas to check.

For informational purposes to other readers, attached are the photos for engine control mount solenoid valve and intake air control solenoid valve.

 

Thanks for doing that.Meanwhile I'm going to stop by The junkyard tomorrow and test the connections on an Accord at the junkyard and see if I get the same readings. If I do, I'm going to clip that harness away and check the wires behind it see if the short is still there. if it's gone then I'm going to suspect the actual wire harness itself that clips into the ELD.

 

Okay, went to the junkyard and tested about five Accords. Three of them were shorted out at the ELD harness and the other two were not. Of the three that were shorted I clipped the harness from the wires and the wires were shorted as well. And I clipped the wires from the harnesses on the ones that weren't shorted and they did not have on a short on the wires. Now I'm almost thinking that these two wires are supposed to be shorted.