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[GMCnet] Heater, A/C blower motor delay relay [message #192277]

Wed, 05 December 2012 09:53

BobDunahugh

Messages: 2465
Registered: October 2010
Location: Cedar Rapids, IA

Karma: 11

Senior Member

On a 78 Royal. The 3 connector delay relay for my A/C blower motor is shown as obsolete ( 366408 ) Why the delay? Is it to dry out the evaporator after shut down? And what's my solution? Thanks, Bob Dunahugh

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Re: [GMCnet] Heater, A/C blower motor delay relay [message #192278 is a reply to message #192277]

Wed, 05 December 2012 09:57

James Hupy

Messages: 6806
Registered: May 2010

Karma: -62

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Bob, Are we talking dash air or roof air. Different workaround techniques
for each one.
Jim Hupy
Salem, Or
78 Gmc Royale 403
On Dec 5, 2012 7:53 AM, "Bob Dunahugh" <yenko108@hotmail.com> wrote:

>
>
>
>
> On a 78 Royal. The 3 connector delay relay for my A/C blower motor is
> shown as obsolete ( 366408 ) Why the delay? Is it to dry out the
> evaporator after shut down? And what's my solution? Thanks, Bob Dunahugh
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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[GMCnet] FW: Heater, A/C blower motor delay relay [message #192285 is a reply to message #192277]

Wed, 05 December 2012 11:18

BobDunahugh

Messages: 2465
Registered: October 2010
Location: Cedar Rapids, IA

Karma: 11

Senior Member

Sorry for not being more clear. I forgot about the roof A/C also has a delay. The delay relay that I'm referring to is in the dash A/C heater unit. The delay relay is mounted next to the standard 3 speed blower relay. Maybe it's a mold control thing by drying out the evaporator after turning off the dash A/C.

On a 78 Royal. The 3 connector delay relay for my A/C blower motor is shown as obsolete ( 366408 ) Why the delay? Is it to dry out the evaporator after shut down? And what's my solution? Thanks, Bob Dunahugh
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Re: [GMCnet] Heater, A/C blower motor delay relay [message #192289 is a reply to message #192277]

Wed, 05 December 2012 11:31

roy1

Messages: 2126
Registered: July 2004
Location: Minden nevada

Karma: 6

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BobDunahugh wrote on Wed, 05 December 2012 07:53

I would agree with your assumption of drying the coil to reduce the chance of a musty odor. My 76 doesn't have one. I would just remove it from the circuit you don't need it.

Roy Keen Minden,NV 76 X Glenbrook

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Re: [GMCnet] Heater, A/C blower motor delay relay [message #192290 is a reply to message #192277]

Wed, 05 December 2012 11:31

emerystora

Messages: 4442
Registered: January 2004

Karma: 13

Senior Member

Hi Bob

On the later 77 and the 78 models the blower dash switch has a MAX position. That connects the blower motor directly to the alternator output which give a higher voltage to it. The sole purpose of the delay relay was to allow the vacuum motors to fully close (or open) the flappers before the blower started. The feeling was that if the blower came on right away the air flow might cause the flappers to not go to the full positions. Apparently, GM had a problem with the air from the blower holding the doors open and the air was not properly directed to the right places (defrost, dash or flloor vents).

The delay relay is the smaller relay at the very top of the panel. It has two leads - on mine they are brown and yellow and one has a male and the other a female terminal at the end of the leads. The leads are approx. 6 to 8 inches long. The female one connects to the male terminal on the lead to the blower motor. The male one leads to the short lead (purple on mine) that goes to the blower relay (terminal 1). If the delay relay burns out you can plug the male motor lead directly into the short female lead going to terminal 1 on the blower relay.

Emery Stora
77 Kingsley
Frederick, CO

On Dec 5, 2012, at 8:53 AM, Bob Dunahugh wrote:

>
>
>
>
> On a 78 Royal. The 3 connector delay relay for my A/C blower motor is shown as obsolete ( 366408 ) Why the delay? Is it to dry out the evaporator after shut down? And what's my solution? Thanks, Bob Dunahugh
>

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Re: [GMCnet] Heater, A/C blower motor delay relay [message #192303 is a reply to message #192277]

Wed, 05 December 2012 13:29

JohnL455

Messages: 4447
Registered: October 2006
Location: Woodstock, IL

Karma: 12

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My delay relay became the "intermitant" relay this year so I did the 30 second patch around per Emery. The good thing is the sexes of the GM connectors allow you to simply patch around it as this was "added on" the last 2 years, they didn't have to modify the existing wiring harness, just looped it in series. My delay relay is still there but leads not connected. Also very slighlty less in-line voltage drop by patching around it.

John Lebetski
Woodstock, IL
77 Eleganza II

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Re: [GMCnet] Heater, A/C blower motor delay relay [message #192311 is a reply to message #192289]

Wed, 05 December 2012 14:20

emerystora

Messages: 4442
Registered: January 2004

Karma: 13

Senior Member

Except the delay relay doesn't delay the shutting off of the blower. It just delays the start up so it won't do anything about drying the coil. It is there strictly to give the vacuum actuated duct doors a chance to fully open (or close) before the blower comes on.

No problem operating without the delay though. Just bypass the relay.

Emery Stora

On Dec 5, 2012, at 10:31 AM, roy@gmcnet.org wrote:

>
>
> BobDunahugh wrote on Wed, 05 December 2012 07:53
>> On a 78 Royal. The 3 connector delay relay for my A/C blower motor is shown as obsolete ( 366408 ) Why the delay? Is it to dry out the evaporator after shut down? And what's my solution? Thanks, Bob Dunahugh
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
> I would agree with your assumption of drying the coil to reduce the chance of a musty odor. My 76 doesn't have one. I would just remove it from the circuit you don't need it.
> --
> Roy Keen
> Minden,NV
> 76 X Glenbrook
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Re: [GMCnet] Heater, A/C blower motor delay relay [message #192333 is a reply to message #192277]

Wed, 05 December 2012 17:25

JohnL455

Messages: 4447
Registered: October 2006
Location: Woodstock, IL

Karma: 12

Senior Member

Right it's 'delay on' only. Not like a electric coolant fan delay relay that runs the fan for several mins AFTER the car is shut off with coolant over the threshold of something like 215.

John Lebetski
Woodstock, IL
77 Eleganza II

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Re: [GMCnet] Heater, A/C blower motor delay relay [message #192348 is a reply to message #192311]

Wed, 05 December 2012 20:43

roy1

Messages: 2126
Registered: July 2004
Location: Minden nevada

Karma: 6

Senior Member

[quote title=emerystora wrote on Wed, 05 December 2012 12:20]Except the delay relay doesn't delay the shutting off of the blower. It just delays the start up so it won't do anything about drying the coil. It is there strictly to give the vacuum actuated duct doors a chance to fully open (or close) before the blower comes on.

No problem operating without the delay though. Just bypass the relay.

Emery Stora

On Dec 5, 2012, at 10:31 AM, roy@gmcnet.org wrote:

>
>
> BobDunahugh wrote on Wed, 05 December 2012 07:53
>> On a 78 Royal. The 3 connector delay relay for my A/C blower motor is shown as obsolete ( 366408 ) Why the delay? Is it to dry out the evaporator after shut down? And what's my solution? Thanks, Bob Dunahugh
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
> I would agree with your assumption of drying the coil to reduce the chance of a musty odor. My 76 doesn't have one. I would just remove it from the circuit you don't need it.
> --
> Roy Keen
> Minden,NV
> 76 X Glenbrook
> _______________________________________________
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Delay on that makes more sense. I would agree with Emery as long as the vent motors have enough vacuum to operate it wouldn't be needed.

Roy Keen Minden,NV 76 X Glenbrook

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