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Old 10-08-2018, 09:42 AM   #1
YE9Longhorn30
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Electrical issue on my 95 K1500

So I was on an almost 300 mile round trip this last week and all of a sudden i lost my wipers (there was spotty showers all the way there and back)and my blower (as in the speed control) will not respond other than some buzzing noises here and there(so it is very tempermental). I pulled the dash apart and i cannot find anything disconnected or shorted out. Are these two connected somehow and i just cant see it? Or is it possible they just croaked at the same time? Any help is much appreciated !!
i have checked all the grounds, cleaned them up and reattached them. Even put a new one on from the firewall to the frame
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Old 10-12-2018, 01:32 PM   #2
LH Lead-Foot
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Re: Electrical issue on my 95 K1500

The 1995 C/K Truck service manual is on paper. I don't know if you have some electrical skills, but a test light will help or a digital multi-meter (DMM) will provide you the ability to do more.

#1 Start with the understanding that if one, two or three items on the same circuit fails, start with the fuse for it as most protect more than one thing.
#1a If you multiple electrical things (4 or more) that quit, start at the supply, like the fusible-links or under-hood fuse center Maxi-Fuses.

(Note; I don't; have anything for 95, so I will use the 98 C/K, close)

A 98 C/K shows 25 amp fuse in the IP box for wipers. If you have "Pulse" or not, GM provides power to the wipe motor or pulse module, ground is constant. Loose either one and your wipers quit.
#2 Start at the fuse box, key-on, engine-off...check both side of wiper fuse. The plastic ATO fuse has windows on top to gain access for testing and should be hot on both sides. Wiggle the fuse as the terminal behind, it plugs into, can be burn't or loose. inspect as needed.
#3 Under the hood, YEL is B+ to "Pulse Module" to a solid state control module for pulse, BRN is input from wiper switch that passes thru 5 resistors creating lower voltage values the module uses for "On-Off" timing. BLK is external ground wire for wiper motor and module.

Heater Fan;
#1 If you have manual HVAC, there is a common problem due to high amperage, that causes the connector to the fan switch to get hot, melt & turn brown. A simple bezel removal, few screws / 7mm hex, but the HVAC controls pulls outward for visual inspection and service.
#2 Find the connector behind the blower fan switch that get B+ 25 amps fuse from the IP fuse box again. Check that connector with key-on, engine-off, the BRN wire should be hot.
#3 High blower fan speed is different. It is controlled by the blower fan switch, but controls the coil of the "High Fan" relay. The relay turns on thru the switch on "High", but connects the blower fan to RED wire to B+ from a 50 amp fuse from the UNDER-HOOD fuse box. (At least in 98, sorry)
#4 Most common cause of blower fan loss is fan switch & connector with burn't terminals inside.

Note in GM Electrical History;
GM started using standard colors, circuit numbers and wire size in metric cross-sectional equivalent charts in 1986. It was proudly announced in the paper service manual in the front of the "Electrical Section #8". They included a chart that provided the tech with "Metric to AWG" wire size for repair.

So, the wiper wire color from an 86 Monte Carlo SS is the same YEL to the pulse module. While the same RED supplies B+ to high speed fan relay with the same PPL to the blower fan B+ when on...it's just all the other speeds pass thru the resistor block and placed inside the air distribution box to keep the "Resistive Wire Coils" cool so they don't melt with air passing over them.

Note in GM Electrical Schematics Format;
Schematics are laid out with B+ at the top, down to protection, then control components, down in order on the page to the device being controlled, then path to ground. This type of schematic design is called "Marshaling"...like a group of soldiers marching into town, thru town, then out of town. Just top to bottom.

(It beats the 12 page fold-out in the back of the book that the left wires where the headlights and last page on the right, was tail lights...everything else was in between) (24 if Diesel) (36 if automatic or police version) Damm, i'm old

Finally;
These are both high amp circuits so even if you find burn't metal terminals, inside the plastic connector, you should check the amperage each device is using with a clamp-on amp meter (Digital one are accurate and reasonable).

Problem Most Techs Make;
You may be finding the "Symptom" of burn't terminals, but the "Root Cause" is the 21 year old blower fan & wiper motor that is wore out and drawing more amperage than the circuit can "Safely" supply without getting too hot. This is where checking "MAX" amperage is a must, otherwise your guessing and will happen again.

Best of luck & lets us know what you found.
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Old 10-12-2018, 08:53 PM   #3
YE9Longhorn30
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Re: Electrical issue on my 95 K1500

Wow. . . If you typed that all on a phone, I'm so sorry. But either way, thank you so much for all that info. I will definately go through that checklist. I'm out of town for a couple weeks so I'll have to look at the truck when I get back home and let you know what I find! It's hard working on my own vehicles right now because all my tools are in storage the wife and I are in a transitional phase and trying to find a new home. Thank you once again for all the good info!
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Old 10-12-2018, 09:12 PM   #4
LH Lead-Foot
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Re: Electrical issue on my 95 K1500

I don't have cable TV, nor a cell phone. After my black lab was poisoned 30 days after my 60th B-day, I don't have my buddy to play with, laugh with or talk too. He knew my schedule and followed me to bed where he used my ankles/feet for his pillow after I fell asleep. Now, I don't sleep well. That's life I guess.

Hope my post helps.
Just helping others learn.
10-4, Over & Out!
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Last edited by LH Lead-Foot; 10-14-2018 at 12:18 PM. Reason: not positive, trying to make it better
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