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Re: I successfully reverse engineered and enhanced the ICU
I recently came across my first USDM example of a Civic/CRX that does not have a wire that provides the washer pump signal to the ICU. It is a 1990 CRX DX built in Japan.
The additional feature that runs the windshield wipers when you spray washer fluid on the windshield will not work for a car that does not have that wire.
Re: I successfully reverse engineered and enhanced the ICU
My intermittent wipers were being weird so I ordered one through ebay and just installed it. Simple installation and works flawless. It is Soo good to have the option for a new ICU and one less thing to worry about going bad randomly.
Re: I successfully reverse engineered and enhanced the ICU
FYI for anyone within easy driving distance of Great Falls, Virginia — I'll be at Katie’s Cars & Coffee tomorrow morning (7/5/2025) showing off my 1990 Civic Si.
I'll bring a few ICUs with me, available for $20 off the eBay price. I'm happy to help with installation if you'd like.
Just remember — Katie’s wraps up before 9 AM, so come early!
Re: I successfully reverse engineered and enhanced the ICU
This is pretty cool. Personally I do not like modern cars that automatically wipe windshield when the washers are activated. I always spray and let fluid soak and soften the dust and blades before I wipe. I live in the crazy dry desert, and blades tend to stick to the windshield between storms.
One thing, is it possible to add a headlight/parking-light warning chime? I leave my headlights on about once a year in my CRX due to leaving for work when it's dark, but arriving at work after sunrise lol.
Re: I successfully reverse engineered and enhanced the ICU
Originally Posted by 94eg!
This is pretty cool. Personally I do not like modern cars that automatically wipe windshield when the washers are activated. I always spray and let fluid soak and soften the dust and blades before I wipe. I live in the crazy dry desert, and blades tend to stick to the windshield between storms.
One thing, is it possible to add a headlight/parking-light warning chime? I leave my headlights on about once a year in my CRX due to leaving for work when it's dark, but arriving at work after sunrise lol.
It’s already built in, it chimes when the door is open when the lights are turned on.
Re: I successfully reverse engineered and enhanced the ICU
Originally Posted by 94eg!
This is pretty cool. Personally I do not like modern cars that automatically wipe windshield when the washers are activated. I always spray and let fluid soak and soften the dust and blades before I wipe. I live in the crazy dry desert, and blades tend to stick to the windshield between storms.
It would be easy to disable that feature if you don't like it, simply de-pin the wire in the location I pointed to in my June 1st post. For safe keeping you could place the wire in the empty wire location right next to it (because that location doesn't connect to anything) De-pinning is easy and also easily reversed, it is not destructive, you don't need to cut the wire. It just requires a really small screwdriver or something like that
Re: I successfully reverse engineered and enhanced the ICU
These have been selling pretty quickly but, I haven't had any available for a couple weeks because I didn't have any cores to recover the connectors from. I now have a few more available.
Re: I successfully reverse engineered and enhanced the ICU
Originally Posted by GeoMetry
These are compatible with any car that originally used part numbers 38600-SH3-A11 or 38600-SH3-A01. I think that includes all USDM Civics and CRXs 1988-1991. I also believe that I will have a version to replace 38600-SH3-C12. (Canadian Version) The Canadian version is actually less complicated. I am trying to make this thing bullet proof. I eliminated all but one electrolytic capacitor. I am using metal film resistors instead of carbon film resistors. I am specifically adding protections to areas of the circuit that have failed in the past. I used optocouplers to electrically isolate some problematic inputs. My design takes into account the possibility that some folks may have replaced the original light bulbs with LEDs. LEDs can put additional stress on transistors that were expecting a bit more current. If anyone has old ICUs that have failed but not been thrown away please hold on to them. I need the connectors but I don't want to take them off working parts. I am looking into getting the connectors reproduced but not having any luck. Because I am adding a pin to the connector to enable the extra feature I require nine sets of connectors to make eight ICUs. If anyone has advice on how to source reproductions of the connectors I would love to hear it. I'm going to take a few months to test these before I try to offer the first batch for sale.
I have a 1988 Civic Canadian version. Looking forward to purchasing a unit from you when available.
Re: I successfully reverse engineered and enhanced the ICU
I have not made a Canadian unit recently. I think there is an understandable lack of interest. Do you have a US address I can ship it to? I don't know how much the tariff would be shipping an ICU into Canada and then shipping the core back to the US. Would you be sending a core back? I am thinking the tariff might be more than the core is worth to me. Can you post a picture of the wires going to your ICU? The Canadian version does not support the feature that warns you if you forget to turn off the headlights, is that OK with you? I would only charge you $99 USD plus core fee and shipping for a Canadian unit, they are less complex than the US version so I charge $60 less.
Re: I successfully reverse engineered and enhanced the ICU
Thank you for working on this, it turned out great. I've been wanting to order one from you for a while. My ICU was replaced not long ago so I wasn't in a rush.
Do you know if the headlight warning feature will work on a USDM ED6? Like others, I've left my headlights on by accident a few times and a warning would be great.
Re: I successfully reverse engineered and enhanced the ICU
The ICU including the headlight warning feature will work in any 1988-1991 USDM Civic or CRX. Some aftermarket modifications can affect compatibility. If you have aftermarket modifications, perform this simple test:
Get into the car where you intend to install the ICU, close the door, and turn the key on then turn the key all the way off. Do not remove the key from the ignition.
Open the door. You should hear a series of beeps from the existing ICU, this will be four short beeps followed by a pause and that pattern will repeat once per second until you either remove the key or close the door.
If your car is 1988-1991 Civic or CRX and you hear the beeps your car should be compatible.
Re: I successfully reverse engineered and enhanced the ICU
Its been a couple months since my last update. For some reason only about 20% of folks that get one of the new ICUs send me their old ICU (core) I can't make new ICUs without the connectors and the plastic cases from the old ICUs, so that makes it hard to keep them available. A fellow EF enthusiast recently sent me a few old dead ICUs he had, so I was able to build a few more new ICUs. I posted them this morning on eBay. https://www.ebay.com/itm/126956680099
Re: I successfully reverse engineered and enhanced the ICU
