installing intermittent wipers into a 77 k2500

[honky lips]

It's hard to follow the wires as shown - but anyway;

Try running a jumper from the steel wiper motor casing to the negative on your battery. did that, no change.


Also, and I really have no idea on this, does that motor/module/switch (switch is just not shown I guess) does that group all belong together? I mean are they all from the same year? If so what year?
switch/module are a pair, motor is from an 82. which is the same as the truck that this switch/module works in. 78-84 use the same motor.


And last but not least - I am so red/green color deficient that the color of those wires ... well I can't be sure of any of them, other than the blue and black. ill fix that.


But bottom line - you can take those exact components to a 1980 truck and the system pulses it's ass off - right? yup. perfectly

BTW how many wires feed into the module on the side we can't see?

9, 6 on one plug and 3 on the other



here hope this helps

 

[chengny]

These dwgs are from the 1983 manual (I hope they are wired the same):

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If you wire the circuit just like the dwgs show, and it still doesn't work on pulse...IDK, maybe intermitent wipers are just not in your future.

 

[honky lips]

looks like i got it right.

only thing it that diagram with the motor does not show a park switch.

but i have it wired
gray to low spd wire on motor
black/lt blue to black/lt blue on switch.

somehow i think its in the parking switch wiring that is not letting things work. but i cannot figure it out. it parks properly. but doesnt pulse. it worked in an 83, and an 81. but this 77 is the child of satan. and it will not work. as far as i can tell.

so with that info, if no one can figure out the error. I am sorry but i give up. I have wired nascar series race cars from scratch for a living for 3 years i have built electrically controlled oil heaters that can maintain a certain temp and auto shut on/off at varying temps. I have eliminated wiring to swap ls motors into rat rods and sand rails. And I currently own an auto repair shop. I am well versed in wiring and diagrams/schematics. And this little 6 wire setup has me completely stumped. I even had a friend that does computer and electronic repair for plants for a living. He came to the same conclusion I did. Completely baffled. I have been defeated by a simple wiper system. there must be something in the wiring of the trucks starting in 79 that I cannot find or figure out. And no amount of bench testing has created any results that were satisfying. even trying to mix and match 4 different switch/module combo's. I was hoping I could make and end all, be all thread for doing these swaps but apparently, thats not to be. I forfeit. Theres enough diagrams/schematics and homemade photos in this thread to choke a horse. maybe someone in the future will see something.

IF ANYONE HAS INSTALLED INTERMITTENT DELAY WIPERS IN A 1977 77 CHEVY TRUCK, I WOULD LIKE TO KNOW. HOPEFULLY SOMETIME IN THE FUTURE SOMEONE THAT HAS MANAGED TO PULL IT OFF ON A 77 MODEL YEAR WILL BE ABLE TO CHIME IN AND SET US STRAIGHT. lIKE I SAID, I HAVE SEEN A LOT OF PEOPLE CLAIMING THEY HAVE DONE IT BUT PUT UP NO PROOF, DIAGRAMS, PICTURES, NOTHING. I HAVE NOT SEEN ONE SUCCESSFUL PERSON DO IT. SO IF YOU ARE OUT THERE. GET IN HERE AND HELP US OUT!

i ordered an aftermarket delay switch and will be using that. eliminating the factory switch/module and factory wiring. i will update this thread with how that goes. Maybe while hooking it up, it will flip a switch and i will figure out what i was doing wrong, if its possible at all.

 

[bucket]

Like I said, I've done it in my '77 and it works. I'm 500 miles from my truck though. DO NOT give up! It IS possible!

Perhaps the park switch wiring is the culprit? I seem to remember the one wire going to 12+ rather than the low speed wire, but I very well could be wrong about that. It was several years ago when I did it. My switch and module came from an '83, the wiper motor I bought a reman unit from the parts store (probably told them an '83 for that too).

Hang in there, you will get delay wipers

 

[bucket]

Alright, I'm back at the truck now. Have you actually installed this in the truck or just bench tested it?

Here's how I have it wired under the hood:

I seem to have two yellow wires coming out of the junction block, along with a dark blue and a light blue. One of the yellow wires comes out of the junction block by itself, I have it wired to the low speed and the park switch. The other yellow wire (grouped with the other two wires at the junction) is the 12+ for the wiper motor and the washer pump. The light blue wire goes to the purple colored wire on the motor (high speed). The dark blue wire goes to the washer pump. The final wire under the hood is the black/blue stripe wire that I had to run through the firewall, for the park switch.

Then under the dash:

Pink goes to the dark blue wire. Black goes to black. Gray goes to black w/ white stripe. Purple goes to light blue. Then I have the lighting wire I had to run under the dash, and the park switch wire that I ran through the firewall.

Now, I do not know why my factory wire colors under the dash do not match my factory wire colors under the hood. I do not have good access for inspection because the drivers's door is right next to a pole in the barn. But at any rate, I have told how the motor is wired under the hood (factory '77 wires adapted to the later style motor) and how the switch is wired in the dash (again, factory '77 wires adapted to the later style switch pigtail) and the system worked perfect. I hope this helps.

 

[datto62073]

It'll help me, if I can find time to do mine.

 

[sobitthen]

Saw your post, was going to jump into mine tomorrow, has hi lo but leaves wipers on windshield if I don't shut when down, tried new motor, same issue, thought since it works at allt he pulse relay was installed, it must be either missing or defective, will use your help above and pull my cover off steering to see if relay is there. I remember seeing a few different plug ins floating around under this truck I bought since they tossed an 86 cab onto a 77 truck... missed loads of connections...

 

[hatzie]

Mike Rowand did a pretty decent writeup on converting the older GM wiper motors to Pulse.
http://www.rowand.net/Shop/Tech/DelayWipers.htm

If your 1977 and prior is stock it will not have the same motor as the 78-84 trucks. I updated my 76 to the 78 up motor and a delay module and switch from the 78-80. I had to open the hole up in the dash to fit the switch and do the presto change'o on the wiring... Not a drop in.

A delay module and switch did exist for the stock 77 wiper motor. It's VERY obsolete. Not sure how many were made. Fairly rare option.

This is the wiring diagram for Option CD4 (Pulse Wipers) on the 1977 GM 10-30 trucks. You can find it in the 1977 wiring manual PDF

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[bucket]

Besides being uncommon, it's my understanding that the '77 delay module is failure prone. My '77 actually came with delay wipers, but of course they did not work... which is why I converted to the '78-up stuff.

 

[hatzie]

Likely it was a rush job and the 78 system was better thought out. That didn't last either. 84 brought a new system and the 84 controller was replaced immediately by the 85+... You can use the 85 controller in the 84 trucks so they didn't orphan the wiring that time.

The 77 controller was probably an R-C timer circuit like they used in several of their small cars into the late 80's.
Why didn't GM use a nice stable timer chip like the ubiquitous 555 driving a FET, or a 555 driving a relay, like VW, Benz, Chrysler and Ford??? Gotta be different.