'76 Laguna A/C Blower works only on high

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'76 Laguna A/C Blower works only on high

Post by Shaunaconda on Wed Sep 25, 2013 10:43 am

Is this the resistor going out? What's the part that is attached to the blower motor under the hood...silver-cylinder shape, kinda looks a little like a battery with a wire attached to it?
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Re: '76 Laguna A/C Blower works only on high

Post by ant7377 on Wed Sep 25, 2013 12:15 pm

Could be the dash switch. You can get them easily enough on ebay or I think even in the parts store.
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Re: '76 Laguna A/C Blower works only on high

Post by 1973montec on Wed Sep 25, 2013 6:46 pm

Check fuse
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Re: '76 Laguna A/C Blower works only on high

Post by pila on Thu Sep 26, 2013 2:58 am

The resistor for low & medium speeds is likely failed.  It's mounted in the plenum where the blower is located, with two screws.  Should be a 3-wire connector plugged into it.

The item you described is probably the condenser that's in the wiring to keep blower brush noise out of the radio.

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Re: '76 Laguna A/C Blower works only on high

Post by dynchel on Thu Sep 26, 2013 7:13 am

pila wrote:The resistor for low & medium speeds is likely failed.  It's mounted in the plenum where the blower is located, with two screws.  Should be a 3-wire connector plugged into it.

The item you described is probably the condenser that's in the wiring to keep blower brush noise out of the radio.
X2 I would put my money on the resistor, after you check the fuses.
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Re: '76 Laguna A/C Blower works only on high

Post by Shaunaconda on Thu Sep 26, 2013 10:18 am

Ok thanks guys!
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Re: '76 Laguna A/C Blower works only on high

Post by magic marouke on Thu Sep 26, 2013 3:19 pm

Hmmmm I have something like that . My defroster goes through the speeds no problem but my AC stays on high where ever the speed lever us . Odd .
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Re: '76 Laguna A/C Blower works only on high

Post by thatfnthing on Thu Sep 26, 2013 4:33 pm

magic marouke wrote:Hmmmm I have something like that . My defroster goes through the speeds no problem but my AC stays on high where ever the speed lever us . Odd .  
FWIW, on mine there was a feature where if you have the A/C on and the temp lever shoved all the way to the coldest possible setting, this was the trigger for "Max A/C" and it would override the speed switch and blow high speed all the time.  You had to back off the temp lever just a notch and it then would obey the speed switch.
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Re: '76 Laguna A/C Blower works only on high

Post by RobW on Fri Sep 27, 2013 12:25 am

Hi, I had the same problem with my fan only working on the high setting.  There is an additional component in the fan system -- a relay located on the air conditioner suitcase in the engine compartment.  In my case, the relay was the problem.  The relay is still available from parts places and is easy to replace.

If I remember correctly, on all but the high setting, fan power starts from the dash harness, goes through the fan switch, through the resistors, then to the relay, and then to the fan.  On the high setting, the fan switch just switches the relay to its second position.  In this position, the power flows from the alternator, through the relay, and then directly to the fan.  

If the relay is not working in the first position, all fan settings but high will not work.  

Rob

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Re: '76 Laguna A/C Blower works only on high

Post by texan01 on Sat Sep 28, 2013 3:53 am

Could be the blower relay, but usually when that fails you have every speed but high.

check the Heater/AC fuse under the dash. Or its a bad fan switch. It's a fairly simple circuit.

I'm in Dallas if you need help.

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Re: '76 Laguna A/C Blower works only on high

Post by pila on Sun Sep 29, 2013 8:29 am

For some reason, the parts stores listings sometimes call the high blower relay the "high blower switch" .  So if looking for one, and a counter person can't find "relay" , switch may be what's listed.......just a FWIW....

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Blower Stays On-Even When The Ignition Is Off

Post by g3chevy on Mon Apr 20, 2015 10:57 pm

So I'm working on a new project which is a 75 Laguna and when all the wires to the blower motor relay are connected the blower will not shut off (stays on high), even with the ignition off and the key pulled out. So I have to pull the wire off the relay that comes from the alternator that stays hot even when the vehicle is turned off. I have tested all the wires from the climate controls to the resistor pack and all the wires have continuity with everything unplugged. I've also replaced the climate control head, blower relay, and resistor pack. Any ideas???


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Re: '76 Laguna A/C Blower works only on high

Post by texan01 on Tue Apr 21, 2015 9:52 am

sounds like the blower relay is wired up wrong, or its bad. unplug the two wire plug on it, and then see if the lower 3 speeds work fine when turning the car off. could be a bad ign switch as well.

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Re: '76 Laguna A/C Blower works only on high

Post by g3chevy on Tue Apr 21, 2015 8:10 pm

Triple checked the wiring against a factory GM manual so I know its plugged in correctly. I've replaced the blower relay with a good used one off my other 75 and a brand new one from the parts store so I've eliminated that possibility as well. I've also tried unplugging the 2 wire plug (Pink & Black Wires) from the relay with no change. I haven't changed the ignition switch yet but everything there seem to work fine. The radio comes on when switched on to accessory and the car starts fine. Still think I should try changing it out? Is there a way to check for specific voltage at each of the wires at the relay and/or resistor pack? I'm thinking maybe it has a short in one of those wires??? Thanks for your help.
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Re: '76 Laguna A/C Blower works only on high

Post by Wallyuph on Wed Apr 22, 2015 7:26 am

Check the harness going across the top of fire wall along the Cowel. We had one ounce that had the wires melt together along that spot that did the same thing. The customer was unplugging the fan tell he brought it in. We fixed the wires that were melted to gether and found he had no fuseable link coming off the starter so when some thing shorted it just melted them to get her so two wire touched sending s constraint feed to blower with key off and out.
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Re: '76 Laguna A/C Blower works only on high

Post by g3chevy on Thu Apr 23, 2015 12:17 am

I pulled all the wires out of the plastic holder along the firewall and removed all the electrical tape back to where the wires pass through to the interior. All look fine. Even did a continuity test of all those wires from the climate control head to the blower relay and resistor pack. All came up good. Not sure where else to check.
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Blower Stays On-Even When The Ignition Is Off

Post by g3chevy on Sun May 10, 2015 12:11 pm

Well I gave up on tracking down any faulty wiring after pulling half the dash apart and tracing and testing wires. The solution I came up with is hard wiring the blue wire lead going to the blower motor relay to the purple wire lead totally bypassing the red lead coming straight from the alternator which stays hot even when the car is turned off. Hard wiring these two leads gave me a working a/c system with the exception of one blower speed which is medium high. I though that I would lose the high setting by re-routing the wiring but it works on all settings except medium high which is really the same speed as low. Very strange. But at least I now have cold a/c which is a must here in Houston!



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Re: '76 Laguna A/C Blower works only on high

Post by Limey SE on Sun May 10, 2015 12:40 pm

Very Nice progress buddy !
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Re: '76 Laguna A/C Blower works only on high

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