Washer Reservoir & Electric Pump
This started out as seeking a replacement for the washer fluid bag, in which one of the hanger eyelet corners was ripping apart due to the age of the bag. I came up bone dry on finding a suitable replacement for the washer bag. I did note that my wiper switch had the momentary push of the knob for washer actuation. So I concluded it had the switch contacts. So I moved toward replacing the washer bag with an aftermarket plastic reservoir and pump assembly. I located a package on Amazon that would fit in near the same location as the washer bag and a decent mount that was more than a wimpy, barely plated, steel bracket that would soon turn to rust.
https://www.amazon.com/gp/product/B0731 ... UTF8&psc=1
I preferred the mount of this washer reservoir as it wouldn't rust, was fairly stout and could be anchored securely with 1/4 bolts/nuts, and had a lift off feature of the tank from the mount.
I secured the mount to the inner fender utilizing 1/4 bolts, nuts, split washers and flat washers. Note the upper mount hole of the mounting bracket only has clearance for a 1/4 SAE flat washer. The others can utilize USS flat washers.
Washer Engine Compartment Wiring
The supplied ground wire was adequate in length to reach an inner fender attaching bolt that I decided to utilize as the ground connection point. I extracted the 1/4 slip-on terminal and supplied hot (red) wire from the supplied power connector shell. The supplied hot wire had inadequate length to reach the firewall bulkhead connectors. I consulted the 1971 passenger wiring diagram and the washer pump was fed by a brown wire with a tracer. I have pretty much all the primary colors of both 18 & 16AWG wire, but none with tracers. So I utilized a brown 18AWG wire from the washer pump, tie wrapped to the factory harness, up to the bulkhead connector. I crimped the appropriate slip on contact on to the pump end of the wire and inserted into the plug shell.
https://www.waytekwire.com/item/30075/3 ... ini-Relay/
I crimped the appropriate bulkhead terminal on to the brown wire and inserted it into an empty bulkhead position #22.
https://www.waytekwire.com/item/30030/A ... Terminal-/
Washer Pump Output Hose
I measured the diameter of the existing rubber hose between the washer fluid bag and the nozzle "T" connector and determined it was 5/32. It was not long enough to reach the pump, so I replaced it with a longer length of 5/32 rubber hose. I wouldn't recommend utilizing the cheap, clear, plastic hose that is included with the washer kit.
Washer Cab Wiring
Next, I wrapped the steering column with some shop towels to protect its finish from the instrument cluster that would hang against it, when removed. I removed the instrument cluster.
I then released all the engine compartment connectors from the bulkhead connector. I removed the screws securing the fuseblock and the bulkhead connector assembly and pulled it from the firewall. I then released the clips securing the fuseblock to the bulkhead connector, to expose the cab side of the bulkhead connector.
I opened the harness retainers at the top of the firewall and pulled the main harness from them. I routed in a 18AWG brown wire from the bulkhead connector, along the main harness and up to the wiper switch. I crimped the appropriate terminal on the bulkhead end of the brown wire and inserted into the #22 position of the bulkhead connector. I tie wrapped the brown wire to the main harness. I re-assembled the fuseblock to the bulkhead connector and re-mounted the assembly.
https://www.waytekwire.com/item/30075/3 ... ini-Relay/
OEM Wiper Switch
I released the connector shell from the rear of the wiper switch. I crimped the appropriate terminal on to the wiper switch end of the brown wire and inserted it into the empty wiper switch plug shell position. I attempted to re-connect the plug shell to the wiper switch, but I could not "feel" the proper orientation of the plug to align it with the wiper switch terminals. Out of frustration, I finally removed the wiper switch from its mounting in the dash. I now realized the issue. I was utilizing the now added washer terminal in the plug shell as a guide to mate it with a switch terminal.
The switch did not have a washer terminal!!!!!! Ugh! The switch had the actuation components, but no terminal. I couldn't believe they would go to the trouble of manufacturing two wiper switches, one with the washer terminal and one without. I suppose manpower was still cheap enough in 1971 where it was cost effective to do so.
So I researched the part number for the same switch with the washer terminals. I found a few online. They were all well north of $100!!!!
Aftermarket Wiper Switch
Nuts! I was not going to pay that kind of money for a wiper switch to only gain the washer function. However, I did not desire to add a separate push button to the dash for the washer function, either. We utilized step vans for our business trucks. They utilized a wiper switch manufactured by Cole Hersee (a subsidiary of Littelfuse, now). It not only has the wash function integrated into it with a three wipe cycle of the blades, but delayed (intermittent) wipe, as well. I utilized this same switch to add delayed (intermittent) wipe and mist function (momentary depression of the wash function) to my tractor cab wiper system. It is extremely handy when blowing snow.
The switch I had utilized in our service trucks was the Cole Hersee 75601-14-BX. It has switching and control to operate two wiper motors, even though every application I've encountered only had one. I soon found this switch was priced less than the single motor versions. None the less, it appeared as if it would possibly work well in the D100 application. This same or very similar wiper switch is often utilized in school bus bodies, trash collection trucks, fire trucks, and other vehicles with specialty bodies. They also manufacture a 24 volt version for heavy equipment, so be aware of that if you choose to employ this switch.
The remaining issue was the park function. Cole Hersee offered this switch in versions to support dynamic park, non-dynamic park or both. Well, what is dynamic park you query? Good question and a very important question. Below is an excerpt for Littelfuse/Cole Hersee's web page that answers that question:
What is the difference between dynamic and non-dynamic brakes?
Non-dynamic (coast to park) and dynamic braking or parking refer to Windshield Wiper Switches. Your vehicle may have either one of the systems for bringing the wipers to the home or parked position.
If you are replacing a Switch, you need to know which type it is. Consult your Vehicle Owner's Manual.
For those who need to know how they work, read on...
Dynamic brake:
Essentially, when you turn the wipers Off, they stop when they reach their park position, but they also get retarded electrically to bring the motor to a rapid stop. When you turn the wiper switch Off and the wipers reach the park position (left or right), the armature of the wiper motor is disconnected from the power source and immediately connected across ground. The motor then functions as a loaded generator and develops a retarding torque that rapidly stops the motor.
Non-dynamic brake:
Essentially, when you turn the wipers off, they stop when they reach their park position. When you turn the wiper switch Off the wipers continue to run by a separate set of contacts mounted on the motor, until the wipers reach their park position. At this point the contacts open, removing power, and thereby stopping the wiper motor. If the motor is not in the park position for the wipers, it continues to run until it reaches the park position and the switch opens as before.
Here is a link to a YouTube video that does an excellent job, with great illustrations, of how a dynamic park wiper motor functions and simplified wiring of it. It was intended for wiper motors that are utilized for theatrical or Halloween scares. None the less, the wiring and functional explanation are still relative.
https://www.youtube.com/watch?v=1Ww5-pmiokc
In the case of my D100 and likely any mass produced car or truck since the early '60s, it has a dynamic park wiper motor. Unfortunatley, it does not state this anywhere in the service manual nor does any of the service manuals I researched offer any type of diagram of the wiper motor. The only thing I found was text for testing the wiper motor and the wiper switch. They sure don't make it easy. Anyway, from the test procedures, I was able to sketch out the circuits and what was occurring for each function. The two-speed wiper motor utilized in my 1971 D100 (and many other Mopar trucks and cars) is definitely a dynamic park wiper motor.
So, which Cole Hersee wiper switch should I utilize? The datasheet below lists the different models of wiper switches offered. Any of the 75600 series will work. The differences being whether they will support one or two wiper motors (large trucks, heavy equipment and ag equipment often have two wiper motors instead of linkage to connect wiper arms.) and the type of connector(s), if any, the wiring is terminated upon. You can utilize a two motor switch by just utilizing the wiring for either motor #1 or motor#2, but do not intermix. All the 75600 series switches support dynamic park. Do not utilize the 75601-14 as it does not support dynamic park. The 75602 series is for 24 volt electrical systems.
I was looking for a bargain and came across several compatible switches on eBay that were marketed as being new. Well, they weren't and they were all defective. So after having my truck tied up for nearly three weeks in the shop with the dash hanging out of it, I ordered a 75600-04 from O'Reilly Auto Parts as they had a good price on it and it would be at the local store at 8:00AM the next morning.
https://www.oreillyauto.com/detail/b/co ... 5600&pos=2
The 75600-04 was not my first choice, as it came without a connector and would be just another I would have to install. Call me lazy. I have connectors and terminals on hand to make the 75600-04 a 75600. So that is what I did. NAPA offered the 75600 at a comparable price to O'Reilly, but had none in stock at any warehouse. Amazon also offered the 75600-04.
Well, Murphy, of Murphy's Law fame, must have slept in this particular morning. The 75600 mounting was not only the same size as the OEM wiper switch (7/16-28) it had the same flats on each side so it will fit in the existing dash mounting hole without modification AND they were indexed properly to position the switch knob so it's script was in a level position. Moreover, though this switch's knob shaft is a larger diameter than the OEM, preventing the use of the OEM knob with it, the supplied knob is a near perfect match to those utilized in the D100!
Wiper Blade Parking
Back to the wiper park function. I vaguely remembered the park function of the two-speed wiper motor was more than simply a set of park switch contacts, in the motor, from my college days of working as a mechanic at a Chrysler dealership. This was back in the days of 8-track tapes or as my daughters cruelly refer to the good 'ole days, as when dinosaurs roamed the earth.
For concealed wiper blades, the wiper motor actually has to reverse rotation. This, in turn, requires the supply voltage polarity to the wiper motor be reversed. To accomplish this, the wiper motor is isolated from chassis ground. In a concealed wiper application, the ground connection is within the wiper switch, where it can reverse the polarity.
With a non-concealed two-speed wiper motor, the ground connection is supplied by a brass strap that connects the isolated, floating, ground of the wiper motor housing to the firewall mounting stud. As I do not recall any sweptline truck that had concealed wiper blades, make sure your wiper motor has this brass ground strap from the motor housing to the rubber isolator's steel mounting center. If it doesn't the dynamic park feature will not function and your wipers will park at inconsistent positions depending on whether the windshield is dry, wet, snow covered, hot, cold, day, night or whether there is a full moon.
When the wiper motor park switch contacts mate with the isolated, floating, wiper motor housing that is now bonded to chassis ground via the brass strap, a dead short of the low speed connection to ground is made. This provides the dynamic braking via the retarding effect of the now grounded low speed connection (armature).
Retaining the "Park" function was a must. With an OEM wiper switch the park function, terminal P1, received power from the wiper switch. As the Cole Hersee switches do not provide park power, the P1 terminal needed to be supplied Ign/Accy 12 volt power. I obtained this from a circuit breaker I added. More on this in the next paragraph. CAUTION: Only connect the P1 wiper motor park switch contacts to the circuit breaker. The P2 contact is the park switch contact that mates with the motor housing, when running, and will create a dead short to ground every time the wiper motor reaches the park position. This dead short would trip the internal and/or external circuit breakers. See the attached wiring diagram.
Circuit Breaker Protection
If you have studied the wiring diagrams of the Chrysler vehicles of this vintage, you've probably noted there is no fuse for the wipers. This is because the OEM wiper switch has an internal circuit breaker to protect the switch, switch to wiper motor wiring, and the wiper motor. Likewise, the 75600 also has an internal breaker. However, this circuit breaker offers no protection to the park function, its wiring, nor the wiper motor park contacts. Thus, I added a self resetting circuit breaker in the supply path to both the wiper motor park contacts and the wiper switch, providing double protection of the wiper switch and loads downstream of it.
https://www.waytekwire.com/item/46315/E ... Shortstop/
Wiper Switch Wiring
The 75600 includes and 8 circuit plug. To provide for easy serviceability, I retained this 8 circuit plug and sourced the mating components. In this manner, if I encounter a switch failure, I can simply unplug the defective switch and plug in a replacement.
https://www.mouser.com/ProductDetail/Ap ... 5UQA%3D%3D
https://www.waytekwire.com/item/31031/A ... Terminal-/
https://www.waytekwire.com/item/30031/A ... Terminal-/
I removed the OEM wiper switch plug housing and terminals from the wires. I installed the above referenced terminals on the wiper low & high speed wires along with the washer pump wire previously routed in. I spliced on to the switch power supply wire, 12LB, with additional #12 wire and routed it to and terminated on the battery stud of the circuit breaker. I also routed in a new wiper switch power wire, #16LB, from the switch plug to the circuit breaker load stud.
I did not want to splice to the P1 wiper motor wire, #18DB, as the wiper motor had a separate harness and I desired to maintain the ability to disconnect and remove it, if need be. So I installed a single position Molex disconnect plug in lieu of a splice. This is pictured in the photo below directly behind the wiper switch connector. The extended P1, #18DB, wire was routed to the circuit breaker's load stud.
Note the shop towel placed over the instrument cluster opening in the dash. It has an extremely sharp edge and I sliced my hand on it.
The additional wiring depicted in the above photos is that I added for the trailer brake controller, trailer power/battery charge feed and a horn relay.
References
