Windshield wiper wiring 1974 Spider

[18Fiatsandcounting]

The wire diagram I have for the 1982 wiper circuit shows the following:
...
Wiper delay timer

Does the '81 model have a wiper delay? I've owned only one '81 model and I doubt I ever worked on the wipers. So, my info might be based on the earlier versions and thus incorrect. Morale of the story: Bryan is often wrong when it comes to "newer" spiders.

-Bryan

[spider2081]

Does the '81 model have a wiper delay?

I believe all Spider have the delay function.
The early Spiders had an electric field wiper motor and this allowed a rheostat to be used for speed control.
By the mid 70's permanent magnet field motors became more cheaper Fiat switched to the permanent magnet field motor. That brought the elimination of the rheostat speed control being replaced with a 2 position speed switch.
Although the steering column switch changed through the years the wiper function through 82 has 3 positions
off/park
delay
on continuously
Then the 83-85.5 column wiper switch included the speed switch functions
of/parkf
delay
on/slow
on/fast

[spider2081]

in previous replies I stated the delay was RC time constant based. Being OCD I opened one I had in the basement to make sure I was posting good information. I'm wrong the delay relay is activated by a thermal device.
That could explain why the first few delay cycle times are noticeably longer than rest.

[18Fiatsandcounting]

Does the '81 model have a wiper delay?

I believe all Spider have the delay function.

Yes, 'tis true, and I worded my question wrong. Does the '81 (or later models) have a variable delay, so that the time between intermittent swipes can be varied? Not the wiper blade speed, but the time between single swipes.

My understanding was that the delay between intermittent wipes was simply a function of the thermal switch inside the intermittent cycling relay. I suppose one could configure the wiring for that thermal switch to provide different times between swipes, such as 2 seconds, 5 seconds, 10 seconds, or what have you. But that would not be stock.

However, you would have to rewire the thermal switch in such a way that it didn't also reduce the voltage to the wiper motor which would simply cause the wiper blades to move slower.

Perhaps I've led this thread far enough astray!

-Bryan

[spider2081]

However, you would have to rewire the thermal switch in such a way that it didn't also reduce the voltage to the wiper motor which would simply cause the wiper blades to move slower.

I believe the thermal switch operated the relay and the relay is what makes the clicking sound. The relay contacts power the wiper motor. I think adding resistance to the thermal switch circuit could increase the the time between sweeps without changing the voltage that operates the wiper motor or sweep speed.
Thee most common complaint with Spider windshield wipers is they are too slow. Not sure increasing the delay time is worth the effort.

[Yadkin]

The only issue is that when the interval switch is set to infinity the relay does a series of odd clicks.

I can no longer get your diagram links to open.
The wire diagram I have for the 1982 wiper circuit shows the following:
steering column switch
Wiper delay timer
Wiper speed switch (2 position)
windshield wiper motor assembly/park switch

I don't know what you are calling the " interval switch"

As I refined the diagram I deleted the older versions. This is the current one that I have bench tested:
https://drive.google.com/file/d/1IPFcdT ... sp=sharing

You'll need to right click on the link and select "copy link address", then paste into a new browser window.

The "interval switch" is a dial that turns to vary resistance from three to six ohms, plus a "click" to infinity. The white/black wire from the column switch needs to be connected to ground for the circuit to work properly. When connected directly to ground, the interval relay triggers at 2-second intervals. The interval switch varies the delay between one and two seconds. When the switch is set to infinity, the relay "stutters". That doesn't seem to be much of a functional advantage.

I got the circuit to work, just not as I expected, so it's probably not correct. It would seem that the potentiometer should increase the delay, and the infinity setting cause the relay to default to two seconds.

[18Fiatsandcounting]

The "interval switch" is a dial that turns to vary resistance from three to six ohms, plus a "click" to infinity.

I'm still confused. I could be mistaken, but I didn't think any of the spiders came with a variable delay for the wipers. Variable speed, yes, but not variable delay. The interval switch that you are describing sounds like the brightness control for the dash lights, which did come standard on all the cars.

So are you trying to wire in this gauge illumination rheostat as a wiper delay function? Might be possible, but it would be a challenge.

-Bryan

[spider2081]

I'm still confused. I could be mistaken, but I didn't think any of the spiders came with a variable delay for the wipers. Variable speed, yes, but not variable delay.

That makes 2 of us Bryan.
The time between wiper sweeps when in the delay mode is a fixed time determined by the thermal switch. The output of the delay timer is a voltage pulse that kicks the wiper motor off the park position and it sweeps back to the park position until another pulse out of the delay timer. When delay is selected the wiper is alternating between park, sweep, park, sweep. The sweep speed is determined by the 2 position speed switch. The park time is determined by the delay module internal thermal switch.
I believe to make a variable delay, the delay module would need to me modified so the thermal switch circuit is brought out of the module with additional wires.

[18Fiatsandcounting]

I believe to make a variable delay, the delay module would need to me modified so the thermal switch circuit is brought out of the module with additional wires.

It's not hard to do, in fact my dad made such a pulse generator for our '72 Chevy Blazer. Easy for him, as he was an EE professor at the local university.

I'm sure if you Googled "pulse generator for wiper delay" or the like, you'd find a circuit. As you said, all you would need is a circuit to generate a 12V pulse every few seconds to kick the Fiat wiper circuit out of the park position. In fact, auto parts stores might sell such a beast for $20 or so.

Fiat chose to use a lot of thermal switches and other simple electromechanical devices, although modern cars use solid state electronics.

-Bryan

[Yadkin]

The "interval switch" is a dial that turns to vary resistance from three to six ohms, plus a "click" to infinity.

I'm still confused. I could be mistaken, but I didn't think any of the spiders came with a variable delay for the wipers. Variable speed, yes, but not variable delay. The interval switch that you are describing sounds like the brightness control for the dash lights, which did come standard on all the cars.

So are you trying to wire in this gauge illumination rheostat as a wiper delay function? Might be possible, but it would be a challenge.

-Bryan

The dash dimmer is a different switch. This one is for the wipers, identical chrome bezel as the wiper speed, and a symbol showing a windshield.

[spider2081]

The dash dimmer is a different switch. This one is for the wipers, identical chrome bezel as the wiper speed, and a symbol showing a windshield.

There is no way to know for sure. It seems to me this rheostat was added by a previous owner and its wiring is not documented anywhere. The 2 wire diagrams i have for 1974 Spiders do not show a rheostat in the circuit. They do show a 2 speed wiper motor and a 2 position speed selector switch.
Early Spiders used a rheostat to vary the wiper motor speed. Best I can tell 1973 and later Spiders did not have a rheostat in the circuit.
Again early wiper motors had an electric field circuit and the rheostat varied the field current to control the motors speed. If the motor you have is a permanent magnet motor no rheostat is shown in the circuit wire diagrams.
Are you attempting to design your own circuit of follow the 1974 wire diagram??

[18Fiatsandcounting]

The dash dimmer is a different switch. This one is for the wipers, identical chrome bezel as the wiper speed, and a symbol showing a windshield.

Yes, the dimmer for the ideograms (like around the heater controls) is a different switch, but the stock version of the two knobs (controls) in the center dash is: wiper speed, and dash gauge light intensity. That's not to say that a previous owner didn't do something unusual, but no spider came stock with a variable wiper delay.

The symbols they used are complete *&^%$, but the two knobs show a flag sort of symbol (wiper speed) and a bulb illumination symbol (the one with a circle with lines radiating from it, and a line through the middle). The latter is dash lighting intensity.

See this thread: http://www.fiatspider.com/f15/viewtopic.php?t=38731

-Bryan

[spider2081]

Are you attempting to design your own circuit of follow the 1974 wire diagram??

Just realized I had a type "O" in this statement I do not know how to edit an existing post so I'll attempt to correct it here.

Are you attempting to design your own circuit, or are you trying to follow the 1974 wire diagram??

[Yadkin]

I joined a new image hosting site so hopefully I can show pictures here.

Here is my custom dash showing the two wiper switches. As you can see that are both for the wiper controls.

[Yadkin]

The interval switch has a "open circuit" detent followed by a potentiometer between 6 and 3 ohms. The open function creates a troublesome chatter in the relay, so I made a minor adjustment to the internals of the switch to convert "open" to "closed" circuit.