RESISTOR & RELAY, BLOWER FAN MOTOR- Where is it located?

[ehcees]

1971 Chevy Cheyenne 10 Fleetside Long bed, 350 V8, AT, AC. VIN: CE141Z652379 Built: 5/12/1971 Fremont, CA. Sold new: Kelsey & Sons Chevrolet, 390 HWY 246, Buellton, CA. Order# TNL098 Zone 34, Dealer 270. Customer Order. Weight 3677 (unloaded)
Factory AC
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From ehcess: Thanks Guys for talking about the Resistor & Relay, Blower fan motor. We need a little more clarification to distinguish between the resistor & the relay so here goes:

1. Cdowns said: The resistor is located over on the passenger side by the heater box// the easy way is to just follow the lt blue, drk blue and yellow wires coming from the heater control switch.
1.1 ehcees replies: Yes, I know that the resistor is suppose to be on the passenger side by the heater (or air box) box behind the glove box, but I do not see it. Can you tell if the resistor is mounted on the heater box (air box)& where? As to the wire colors, the Chevy Dealer parts man (Richard) seems to believe that Factory AC means different set up than no AC. Is this true? See below 2.1 for relay issue.
2. clay68C10 states: If it's high speed that doesn't work, you may need the relay. I think it's on the airbox under the dash. The resistor only runs low & medium speed. Can you hear the relay click when you put the fan switch on high?
2.1 ehcees: Will try high speed fan position to see if relay clicks. Relay is mounted on passenger side, heater (air) box right veridical side. Recall that this C10 has factory AC. There are two connectors attached to the relay: One has a single orange wire. Second connector has blue, another orange & purple wire. Total of four wires on two connectors. Mechanic & parts guy (Richard) said I need resistor. Since I already bought resistor, it would be good to install it even if your correct in telling that relay is reason for no high speed. Do you know the exact location of the resistor?
3. GMC Jim states: The relay is located at the right side of the glove box on the firewall. Check that the relay is grounded before you invest in a new relay.3.1 On ehcess 71 Chevy with factory AC, the relay is mounted on the right side (vertical) of the heater box behind glove box. Not sure what grounds the relay as it is attached with two small screws to the plastic heater (air) box. Perhaps one of the four wires to the relay is a ground? Do you know? See 2.1above for relay wire colors.
When we finish this thread, then we will all know the resistor location, if factory AC makes a difference & if the relay controls fan high speed plus how the relay is grounded?

Glove box door Service Parts Identification label States-The special equipment listed below has been installed on this vehicle. For proper identification of replacement parts be sure to specify the applicable option numbers.
Option no. & Descriptions: Important: Retain this plate as a permanent record.
W/Base 127
B85 Belt Molding
F52 Front Shock Absorber (bumper guards)
LS9 350 CU IN V-8 Engine (4 bbl)
N40 Power Steering
VK2 Tool & Stowage Box
Z84 Custom Sport Truck
621 Saddle Vinyl Custom Trim
A11 Tinted Glass
C60 4- Season Air Cond
G70 R Susp- Leaf Spring
M49 Turbo Hydra-matic
U63 AM-P/Button Radio
Z53 Amp-Oil-Temp Gauge
463 White & Ochred (yellow sort of)

[dwaite72lnghrn]

Nice truck. I am confused by the post. Are you asking where each is?
Resistor on an AC truck is in the top left of the heat box held in by 2 small hex head screws (It looks like 2 coils of wire), It has 1 plastic connector with 3 electrical connections(light blue,dark blue, yellow). The Blower relay is a small metal can on the right side of the heat box behind the vacuum actuator on the passenger kick panel, it has 4 electrical contacts(small orange,dark blue,purple and heavy orange) + a ground (black wire).

[Huck]

By far the most common problem with fan speeds on an A/C truck is the grounding of the relay. I would not fix anying before making sure that this relay has a good solid ground to the body.
Very nice truck---you can download wiring diagrams so you can trace this design for yourself and save time--use as reference for future opportunities!!
Do a search for wiring diagrams. You can also buy a copy of the factory shop manual for around $25. which will also help you with keeping this puppy running like new.

[Andy4639]

Resister is inside the air box inside the cab. if you take the screws out of the bottom box peice where the heater air b;ws out then take the next section off you will see it inside the box.

[roughedup72]

are you saying that you dont have a high speed on your fan? If so, I had a similar problem with a van I own. All the speeds would blow except high, after many a hours of cursing and head scratching and replacing parts I found that all it was was a bad connection for the main power wire going to the RELAY not the RESISTOR. It took several weeks of troubleshooting to find this out.And a lot of beer as well.

[ehcees]

11/14/06
Here are ehcees replies in green to the latest respondents to the Resistor & Relay location? All of your input is greatly appreciated despite several contradictions between your answers as noted below. (What's a Mother to do?) Please state if your truck has factory AC or not in all replies. Were confusing each other by different setups for no AC & Factory AC. Thanks to all.
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4. dwaite72lnghrn Nice truck. I am confused by the post. Are you asking where each is?
4.1 Yes.
4. Resistor on an AC truck is in the top left of the heat box held in by 2 small hex head screws (It looks like 2 coils of wire), It has 1 plastic connector with 3 electrical connections (light blue, dark blue, yellow)

4.2 See #6 below for contradiction on resistor location.


4.3 Your correct on visual description of resistor compared to new resistor bought from Chevy dealer, GM P/N: 03929055, which has 3 spades or tabs to meet the connector. ehcees has removed glove box & does not see resistor on the top of heater/AC box. Please tell if the resistor is visible or further to the left of glove box hole & out of sight?

4. The Blower relay is a small metal can on the right side of the heat box behind the vacuum actuator on the passenger kick panel, it has 4 electrical contacts (small orange, dark blue, purple and heavy orange) + a ground (black wire).


4.4 On ehcees truck the relay is mounted on the right side of the heater box next to the vacuum actuator & kick panel, but not on the kick panel. There are two connectors attached to the relay: One has a single orange wire. Second connector has blue, another orange & purple wire. Total of four wires on two connectors. (See 2.1) ehcees does not see any BLK wire going to the relay as you state. Otherwise we agree on wire colors for relay.


5. Huck By far the most common problem with fan speeds on an A/C truck is the grounding of the relay. I would not fix anything before making sure that this relay has a good solid ground to the body.
5.1 Relay is attached to right side of heater/ac box by 2 small hex screws. Since box is plastic, ehcees assumes that one of the four relay wires must be a ground. See 4.1, above, for relay wire color controversy (BLK). Recall that the two lowest speeds do work & high-speed fan is dead. What does that tell you about grounding?
5. Very nice truck---you can download wiring diagrams so you can trace this design for yourself and save time--use as reference for future opportunities!! Do a search for wiring diagrams. You can also buy a copy of the factory shop manual for around $25. which will also help you with keeping this puppy running like new.


5.2 Electrical diagram or wiring guide on these trucks & old cars were often another book from the Shop Manual. If you can provide a specific web address for wiring & shop manual that would be welcome. Chilton 1988, 1970-1987 book is worthless on my relay/resistor question, but was good on many mechanical matters.


6. Andy4639 Resister is inside the air box inside the cab. if you take the screws out of the bottom box piece where the heater air blows out then take the next section off you will see it inside the box.


6.1 See #4 above for contradiction on resistor location. Who is right? Tell if your truck has factory AC or not?


7. roghedup72 are you saying that you don’t have a high speed on your fan?


7.1 Correct. No high-speed fan & two lower speeds work.
7. If so, I had a similar problem with a van I own. All the speeds would blow except high, after many hours of cursing and head scratching and replacing parts I found that all it was a bad connection for the main power wire going to the RELAY not the RESISTOR. It took several weeks of troubleshooting to find this out. And a lot of beer as well.

7.2 What color is the main power wire going to the Relay? Does your truck have factory AC or not?

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[sneakysnake]

A schematic

[ehcees]

What does "A Schematic" mean? Please write a complete sentance that explains your input. Thanks.- ehcees.

[sneakysnake]

Originally Posted by ehcees

What does "A Schematic" mean? Please write a complete sentance that explains your input. Thanks.- ehcees.

It means.A schematic; is a diagram, drawing, or sketch that details the elements of a system, such as the elements of an electrical or electronic circuit or the elements of a logic diagram.

[Solver]

here are some pics of heat and heat/ac boxes if anyone needs to describe better
First 3 heat /no ac
next 3 heat /ac

[Solver]

3 with ac
Thought maybe these would help

[ehcees]

11/15/06 – First are shown answers to prior advised diagnostic attempts:
1. Cdowns said: The resistor is located over on the passenger side by the heater box// the easy way is to just follow the lt blue, drk blue and yellow wires coming from the heater control switch.[/COLOR]
1.2 ehcees: The wires on the fan switch (3 speeds) are brown, 2 yellows, & light blue. All of the wires under the dash are wraped in black plastic. Hence I am unable to trace by color from the fan (blower) switch to the resistor. Please confirm if “heater control switch” is same as the 3 speed blower switch?
2. clay68C10 The resistor only runs low & medium speed. Can you hear the relay click when you put the fan switch on high?
2.2 ehcees: Relay in fact does click when blower switch is placed on high speed. Guess this means that relay is OK?
4. dwaite72lnghrn – Relay wires & colors.
4.4 ehcees: Have looked at relay again & now found ground BLK wire. Hence I stand corrected. The relay wires on my ’71 with factory AC include: Two connectors attached to the relay: One has a single orange wire. Second connector has blue, another orange & purple wire. Total of four wires on two connectors + BLK attached to one of two mounting hex screws.

THE LATEST BELOW:

8. sneakysnake: Schematic image provided.

8.1 ehcees: Thanks. Resistor 3 wires appear to go: Two go to control switch. (Please confirm is this is the 3 speed blower switch?) & 1 wire to Blower Motor Relay. However, schematic does not include the heater box so it does tell where the resistor is mounted. Do you have an opinion for location of resistor with factory AC? How do I download the schematic attached image? I see no link of button to do this?[/COLOR]
9. Solver: Provided 3 photos no AC box & 3 photos of with Heat/AC box.

9.1 ehcees: These Heater box photos are great. In the 3 photos with AC, I see no resistor in the photo as it was probably taken off the box to remove the box from truck. Can you tell where the resistor was mounted on the heater box that is for factory AC?Photo #3 (No AC) seems to show the resistor on bottom left, but ehcees can’t tell what piece of the heater box the resistor is attached to. Can you tell us? How do I download photo attached image? I see no link of button to do this? One of your truck photos has my two tone colors. Not my favorite, but then Ochred was a 1970’s thing.

[Solver]

Thought I would just finish this up by showing exactly where things are.
This is for AC

last pic shows resistor location for NON AC

[ehcees]

ehcess now finally can see the location of resistor inside the right side of heat/ac box in your first two shop manual page photos for factory AC. How fortuitous to have the applicable manual & thanks for answering my question.
On the second shop manual page photo, two metal access doors are shown as #3 on the box bottom. What purpose do these small flap doors serve & should I care?

Can the right section of box be removed without touching the other sections? Or please tell best process to minimize box section removals to access resistor?

If you need a source for manifolds etc, I can supply one known to be honest, fast ship, less than half local parts store price & better than originals. ehcees has no affiliation with this supplier. In 2005 the exhaust manifolds were replaced after 192,000 miles. Were from original 350 motor & put on Goodwrench current motor in 1992 or 48,000 miles ago.

[krue]

I'm just curious, why do you refer to yourself in the third person? Great vocabulary btw.

[drink2mny]

drink2mny now understands where the resistor/relay is...

drink2mny thanks echees....

[ehcees]

ehcees learned decades ago to use proper nouns rather than pronouns in business letters. Reason is to avoid any mix up as to who is being refered to or quototed. The issue of the reader being focused on the contigous concepts expressed through a series of sentenaces became much more pronounced with advent of E-mail. This means fewer persons read or pay attention.
More recently experts have advised refering to self in the third person when composing E-mail & going for a larger font size than default. Bottomline goal is effective communication. Hope this helps.

[ehcees]

ehcees says your welcome, but thank SOLVER for the Heat-AC box photos & shop manual page photos that show the resistor local for both AC & no AC. (different) Also thanks to Sneakysnake for schematic wiring diagram on Heat-AC. You can thank ehcees for his time & info organizational skills & green text, if you like it. Suggest that all photos be downloaded & saved as they are valuable info that took three days to get.

[krue]

Originally Posted by ehcees

ehcees learned decades ago to use proper nouns rather than pronouns in business letters. Reason is to avoid any mix up as to who is being refered to or quototed. The issue of the reader being focused on the contigous concepts expressed through a series of sentenaces became much more pronounced with advent of E-mail. This means fewer persons read or pay attention.
More recently experts have advised refering to self in the third person when composing E-mail & going for a larger font size than default. Bottomline goal is effective communication. Hope this helps.

Actually in my case it makes communication less effective, because I feel like I need a translator. The larger font size is annoying because I read at a fast rate and have to scroll to finish reading a post. The "quote" function on the bulletin board is useful for making it absolutely clear who is saying what.

Btw, if you think the info provided is helpful, feel free to post a thread containing the pertinent photos and captions on the FAQ board.

[ehcees]

10.3 ehcees notes that Krue is Forum Staff. As such, please be advised that unless Krue feels that ehcees has factually violated any terms & conditions of your web site user agreement (NOT), then ehcees is not at all interested in hearing about Krue’s commentary as to ehcees right to choose his preferred English Composition method, text color & font size. Smaller fonts are annoying to the vast population of persons with less than perfect eyesight. Can you show a little sensitivity for accommodating middle aged & beyond eyesight?

Krue states that he feels like he needs a translator to understand the use of proper nouns rather than non-descript & often misunderstood pronouns. That is your problem & the minority reaction. Please keep in mind that ehcees is an educated professional with decades of proven results & experience communicating to all levels of education achieved from high school dropouts to PhD scientists & engineers. The top-level lesson is to produce based on serving the majority & not solely for Krue.

Ehcees has no idea what Krue’s use of the abbreviation “Btw” means. However, ehcees agrees that posting heater box & schematic photos for locating the blower resistor to the FAQ board is a good idea. Please don’t go away mad, just go away. No reply requested or wanted.

Live the life you love & love the life you live. You can sit in the waiting room or wait in the sitting room. Life is what happens while your making other plans.

[krue]

Krue would like to point out to ehcees that there is a forum skin that accomodates those of us with poor eyesight (we have several members with significant eye problems and we accomodate them).
I never said you couldn't communicate in any way you like, I will point out that the majority of the people on this board will find it confusing and irritating, which is a barrier to communication.
BTW means By The Way. I fully understand the use of nouns and pronouns and SPELLCHECK and I am a very good communicator as anyone who has spent any time on this board can attest. I also understand the standard use of the English language, which from trying to read your posts, you do not.

BTW....I don't need your permission to reply to your thread and to your posts.
Thank you

[Liz]

Liz would like to point out, that telling the forum staff what to do and not to do, is a bad idea. Liz would also like to point out that this website and its owner reserve the right to off any account at anytime for any reason. Liz will also ask that everyone play nice from here on out. Liz will make one last request to type in proper font size as when she uses the larger font style for those poor of sight, these posts take up 2 pages and slow down her machine. Liz is also closing this post

well cause its beyond on my nerves at this point...... cut the crap, play nice and act right.. its a community we all have to get along



there is a quote system put in place, to be able to make reading replies to specific questions easier. If you are unsure of how to use it, or would like help, just ask.