Hey there Everyone I have always crunched on these forums for my last two civics and almost always found the answer but this time I seem to have run out of luck...

So ill explain my situation:

I own a 1999 Civic Hatch DX, with no A/C and while it was cooler in my area I was fine but now that the summer has officially hit I Am dying. So i decided to run on over to a local pick n pull and pulled out everything for the AC swap.

parts I pulled:
Condenser + Fan
Compressor (2006 replacement),
Dryer
Lines
pulley
Evaporator + Box
Front engine/ accessory harness
Relays + fuses.

i put it all in over a weekend and i noticed the condenser fan wouldn't kick on so naturally i suspected it was because the relay was bad so i swapped it with my front radiator coolant fan relay and it still didn't work, but when i used a paperclip on the power side of the relay it would run the fan no problem, and the ac would work great. So I know that the wiring to the fan is solid the issue seems to be from the fuse panel to somewhere in the cabin. the next day i I figured the whole ac system wouldn't turn on until the loop was pressurized properly, so i brought it down to my local shop and got it evacuated and recharged to factory spec,

the issue persisted. and I had a weird idle issue where it would have a bumpy idle and in the very low rpm range and almost stall, so i cleaned out the IACV and the idle seems a little better.

I think its tied to the ac fan not coming on to cool down the loop and causing the compressor to turn off and on at a fast rate cause weird idling issues.

any help would be greatly appreciated...

first post btw

 

I hope you installed a new receiver/dryer. Did shop that evacuated and recharged system ask?

Does the A/C compressor clutch engage when you press the A/C button?

In the fan relay socket, did you jump pins 2-3 or 4-3 to make the fan run?

 

Compressor does click on

New dryer is installed
​​​​​​
I believe pins 3&4

 

Repeat jump test on pins 2-3 with key OFF. Does fan run?

 

No such luck

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Only way that works car on or off

 

Your hood fuse box or AC diode is bad. Test the AC diode. If it is fine, replace the hood fuse box.

It's no longer relevant, but I told you to do incorrect pin jump tests.

I should have said jump 1-2 or 1-4.

 

Are you sure?
Is there anyway to verify this easily?

 

See my edited post.

And yes, I am sure assuming that you jumped both 1-2 (shown in your pic) and 1-4.

However, the 1-4 test must be done with Key in ON(II). Try that if you haven't already.

 

No luck

Only jump that works is 1,2 and works with key in or out of ignition

How would I go about testing the diode?

Edit: thanks for the diagram it's much better quality than the one I had previously

 

Do you have a multimeter? Most modern digital multimeters have a diode testing function.

I believe that the diode is located on the underside of the hood fuse box.

 

Yes I have one ill pull it apart right now one sec

 

Disconnect the battery!

 

I got it open what should I be looking for?

And I did lol thanks for checking haha

 

The following shows the location of the A/C diode.

 

So I should check resistance on those two points on the fuse box or access it from the under side?

 

The diode is actually on the top side of the hood fuse box. Post pic and I'll circle it for you.

Edit: The famous tech8 beat me to it!

 

Remove diode from fuse box.

Set multimeter to test diode. It has two pins.One polarity across the pins should yield a reading and the other polarity should not, if diode is good.

 

 

The test is done on the removed diode, not the fuse box socket for the diode.

​​​​​​​

 

That could be my problem as there was nothing in the socket to begin with I didn't know I needed one when I was pulling parts

Can I pick one up locally (generic auto parts store) or is it a semi hard part to find

 

PROBLEM SOLVED.

Buy an AC diode (Honda dealer) and install it or return to junk yard to retrieve from donor Civic.

 

If that's works it would be great! Have a link to the proper one I should buy? From O Reillys or auto zone?

junkyard is closed


Don't wanna mess around and get the wrong one

 

You can see the Honda part number here:

https://www.bernardiparts.com/Honda/...&assembly=1887

It's part #1.

You can also search for it at local auto parts stores. Not sure if they will stock it.

 

Great thanks for your help wouldn't have guessed that especially since the diode slot on my 7th gen has nothing in the diode slot and ac runs fine... Kinda weird I'll run down there and see if they have one ill post my outcome

Thanks again!

 

The 7th generation Civic A/C circuit lacks an AC diode.