Hi,

I have a 1993 Honda and it needs a new fusebox because essentially that year used a built-in ELD sensor that is essentially a mini transformer used for current sensing and the sensor died. I am hesitant to just go to a junkyard without knowing how to properly test a fusebox to make sure everything works, including the ELD. Anyone have an ideas and/or experience testing automotive fuseboxes and transformer-based current sensors?

Many thanks in advance.

 

I am not familiar with fuse-blocks using a current transformer to sense current. THAT is a totally new one on me. It seems that the current sensor must communicate with the body control computer to decide if the current is correct for the commends given. So you will somehow need to verify that the sensor output is correct.

 

Hi MisterBill,

Thanks for replying to my post. In the car I have, it's indirect: the power to the alternator is variably too high or too low (it's an older generation, plz see the following link for roughly how the sensor is used: https://www.hamotorsports.com/pages/electronic-load-detector-eld). My basic understanding of how ELDs were designed from the research I've done is that they're design was, and maybe is, similar to what is described in the following post: https://www.coilcraft.com/en-us/products/transformers/power-transformers/current-sensing/. I've checked other hardware/fuses in the power circuit. I've even checked wired continuity. I'm pretty sure my ELD is faulty. And I just so happen to own the year the ELD was not replaceable without replacing the whole fusebox. So I'm trying to see if there is a way to tell if a fusebox, including the new ELD, is any good if I were to go to a pick-and-pull/junkyard. I don't want to replace it with something as bad or worse. Curious about any thoughts, many thanks.

 

I don't have any ideas myself as to how to test a junkyard part so I apologize for that.
I do however strongly suggest back probing connectors while connected instead of continuity testing. A small paperclip or back probe leads poked in between the seal and wire on a connector can reveal problems you won't see otherwise. Continuity testing doesn't adequately load the wire and as long as there is still a hair width worth of wire that is still good the test will show a good connection.
Chances are though you are on the right track since it was enough of a problem to make the part replaceable. I wish I had more to offer.

 

I am trying to imagine what sort of (not defective) regulator allows the alternator voltage to vary excessively. OR is it that the wiring in the car is so poorly designed that there is an excessive voltage drop??
OR, is the "ELD" actually an Electronic Load Detector that allows the controls computer to verify that the different devices are drawing the correct current when the controls computer switches them on?? THAT makes a bit of sense.

 

The hamotorsports link in #3 does a good job in describing how it all works.

 

Consider that any tester scheme will need to both power the package and also have to simulate the loads that generate the signals, AND interpret the output of the sensor nodule.
After reading that description in post #3 it seems that there are many potential points of failure.
BUT in addition, I see the comment: " In the car I have, it's indirect: the power to the alternator is variably too high or too low (it's an older generation, plz see the following link for roughly how the sensor is used." while the link tells us that the system varies the alternator output quite a bit. Based on that, it may be perfectly OK for the alternator voltage to be dropping down to 12.3 volts and then jumping up to the much higher battery charging voltage. Thus looking at the alternator voltage itself is not an adequate means to verify anything.
HAS THE TS read and understood the rather bizarre scheme used in that alternator control scheme??? Has the battery not been being properly charged?? It seems to me that other ways to evaluate the operation of the charging system need to be used.

 

HAS THE TS read and understood the rather bizarre scheme used in that alternator control scheme???

I have to admit that thought crossed my mind too. It actually makes a bit of sense why they would do it that way, but also makes it 100 times unnecessarily complicated. More information is needed.

 

That brand of autos is notorious for making things very complex. In this case a higher resolution monitoring of the battery voltage, to provide closer alternator regulation, would be vastly simpler. BUT that would demand better production tolerances.