I assume the low and high speed wipers work and park normally. I think the wiper module is essentially a timer circuit built around that nand-gate chip, and the relay puts power on the low speed wiper wire just long enough to get the wipers up and moving, then the normal park circuit runs it through the rest of the sweep. If you've got it in circuit, it might be useful to put a meter on the pins of the chip and transistor and see if you see any cycling. Verify that see changing resistance between the wiper delay pins from the staulk to eliminate a wiring problem or bad potentiometer in the staulk.

It's been a while since I had one of these apart, and didn't recall the surface mount stuff on the bottom. The couple I've repaired were either bad solder joints on the connector pins or the relay, or burnt contacts in the relay which I assumed were caused by a struggling wiper motor pulling too much current. If you haven't already, inspect all the solder joints really carefully, and resolder the ones for the relay. I can see some rings around those pins in the picture, but not sure if that's because you resoldered them already. Probably 3/4 of the electronics repairs I do these days are either bad solder joints or bad caps, sometimes causing other things like drive transistors to blow.

You're doing great for a "newbie". I sometimes take it for granted that everyone knows basic electronics, then I I have friends who are fantastic at rebuilding engines and welding that can't figure out how to wire a lightswitch,

 

Hi,
Since I had bought the used working one, I can use your advise to measure the actual voltage on each component side and do some googling and compare to specification of transistor, diode, caps,etc to determine what is the code or series are. Then map them into electronic schematic.
I can identify many of them except Power transistor nearby the relay and SMD capacitors and that little black SMD parts which has 3 pin ( a couple of them installed on PCB).

I hope that I had done all the re-soldering properly on each point. I did connection test using multimeter to ensure all installed parts is connected properly. So I can remove them from the potential root causes. I did a repair previously on 2013. It was only a10uF capacitor nearby the PIN 1 input from connector C230. it was blown up and leave a burnt trace under the capacitor. Replace it and it was working OK. But this time, I had power transistor, 68uF, 22uF and 4.7uF failed all together. I agree they all might failed due to aged. Testing and measuring each point for connection and re-soldering are the easiest ways that we can do before replacing some parts.

I am trying to do reverse engineering for this circuit or cloning in the simple word. I realize it will be a tough job for me due to my knowledge. At least I can start with the thing that I know and asking and share some information to make it work. I don't have enough knowledge to map this circuit into working electric schematic yet. What I can find is the intermittent wiper using low speed wiper but the delay is managed by Quad 2 Input NAND Schmitt Trigger circuit (MC14093BCP) and 12V SPDT Relay (Fujitsu I guess). I am working now to clone this PCB using Sprint Layout 6.0 and those several parts prevent me to complete the cloning correctly.
Then I can remake the PCB with better board quality since this board is easily broken by too much heat rather than today PCB. There are a lot of Chinese PCB manufacturers that offer PCB build with only less than $5 for 5 pcs. Some friends had tried them and it is quite decent to try in quality vs price (value for money) perspective.
Anyway, thanks for your advice lawsoncl.

 

I tried to re-check each connection and draw the PCB layout. Some parts such as SMD resistors and SMD Capacitors had been identified but the small black 3 pins I cannot identify them and so does power transistor. The other thing, All diodes code are also strange, I got no luck to get the correct PN/ code.



Here it is, please give your feedback to get it right.



Thanks.

 

I got all SMD caps and resistor identify but failed on Diodes and that black 3 pins which I assume SMD transistor. Those diodes code I couldn't find the match.


Here is the PCB lay out. It is so many things that need to be done. If those parts are identify then I can try the build one for testing. Please give your feedback or correction.
Thanks.

 

Now it is only left for all diodes type and Power transistor. I couldn't find the type based on code. Funny thing all SMD capacitors, transistor and diode can be found.
Here is the cloning PCB looks like

 

Greetings fellow XJers. I'd like to discuss resurrecting this project. This is by no means my area of expertise but I work with a few EEs who could probably help if I can show them a schematic. Based on what firawan242 has done above, it seems to me the next step would be to determine the connectivity of all of the inter-layer connections to figure out the parts of the circuit that we can't see, and then, a full schematic could be created. Am I correct in that line of thinking? Am I missing something? Have you started a schematic at all firawan242?

Going down a different path, does it make sense to redesign this circuit to use a 555 timer chip instead of the relatively obscure MC14093BCP? If I'm reading the MC14093BCP docs correctly, the downside of doing so is that the 555 chip has a very abrupt waveform, with the return switch in the wiper motor doing most of the work while the MC14093BCP looks like it would drive the motor longer. Maybe I'm wrong (more than likely actually...) But anyways, a fine fellow Jeeper over at Jeep Forum did an install using a MXA041, which uses a 555 timer chip. If you click on the "Download User Manual" link off of the below, it shows the schematic; seems easier to implement than what we're dealing with. Plus it's all human size components instead of those tiny PITAs I can barely see any more. The downside of the MXA041 is the same as the OEM board; marginal spec components that warrant an external relay. If we're going to do this, let's make it bullet proof is my thinking.

https://www.thaikits.com/index.php/t...t%20Store.html

 

So I slapped that PCB of yours into CAD, traced over it, put a multi-meter to junk board and have come up with the following changes that I believe need to be made. I also highlighted circuitry that is not populated on my board and has generally been excluded from my further analysis. The capacitor in the upper left on my board in 68uF, not 6.8uF as it appears on your PCB but after looking at it some more, I'm thinking that's just a random white dot.

 

Moving a few things around, I get the following full schematic. Traces highlighted in red are high level signals, mostly just pass-thru, that I've replaced with labels embedded within. For clarity, I've removed this connectivity on subsequent images. Relevant connectivity in the wiper stalk and motor switches has been added.

 

On the below image, physical features that can be measured on the board are indicated with a red dot. Test pads are shown according to the numbering in the the first image; V1, V2, etc. I've found these to be just that, test pads, and therefore can be removed from further analysis and physical boards.

 

Subsequent images simplify things further by replacing the relevant circuit below into simply "Ign Hot" input into the MC14093BCP chip, similarly with "Wiper High" into pins 8 & 9.

 

Taken all of the above simplifications into account, if you really wanted to figure out how this thing works, here's a schematic for you

 

As our luck would have it, one of the modules I had was an aftermarket replacement part with the following PCB layout. Unfortunately it's build upside down and mounted in a corresponding case such that we can't easily use in it place of the OEM. Luckily the OEM board uses a more common '1 Form C' relay, so it's not all bad.


which if you move enough things around yields a schematic of




The fortuitous part of having this aftermarket module is we can now determine what all of the components are !!! TIP120 transistor for TR1, 30V Zener diode for D2, 16V Zener diode for D3 and 1N4004s for everything else. There is the one 1N4004G, which from what I can tell is a reduced Pb version, which makes sense given that it's installed vertically and therefore required more handling. I couldn't cross-reference the labeling on the TR2 equivalent, but no loss there since we already know what it is.

 

Now if we overlay the components of the aftermarket module onto the schematic for the OEM module, we'll notice the following differences. Aftermarket values are shown in red

If we take these differences into account, if one really wants to figure out how this thing works, here's a schematic for you

 

The really notable difference between the OEM and aftermarket module is the addition of the diode to ground off the "Delay Output" -> 33k circuit. Seems worthwhile to add the ability to add the diode if replicating the OEM board. Secondly, one of the common issues with the OEM board is the Ignition Hot trace burning up. By eliminating the circuitry that's not populated on the OEM board, the trace could be made wider. I believe any reproduction of the OEM board should have the following changes

 

While we're at it, it seems to make sense to try to fit a heatsink to the TR1 transistor. The first step in doing so is eliminating the circuitry that is not used on the aftermarket board, namly the BAV99, BAS40 circuit.