Working on "bugs

neely butler

New member
Sep 28, 1998
204
0
0
The heat/AC blower motor will not run on high speed, OK on lower speeds. Is
their a separate fuse for high speed? If so where.
Thanks.
Neely B. Tenn
'78 Eleganza
 
>The heat/AC blower motor will not run on high speed, OK on lower speeds. Is
>their a separate fuse for high speed? If so where.
>Thanks.

I can't find it but I think I remember someone saying that it ran right off
a different source than the other speeds. not sure what that means.
Mine wasn't working the other day and I wiggled the connector around on the
heater box and it started working again. It's accessible through the
drivers side front access panel, near the master cylinder.

Hope this helps

bdub
'76 Palm Beach
In The Heart o Texas
www.web-access.net/~bmassey/
icq # 202333
 
>The heat/AC blower motor will not run on high speed, OK on lower speeds. Is
>their a separate fuse for high speed? If so where.
>Thanks.

I can't find it but I think I remember someone saying that it ran right off
a different source than the other speeds. not sure what that means.
Mine wasn't working the other day and I wiggled the connector around on the
heater box and it started working again. It's accessible through the
drivers side front access panel, near the master cylinder.

Hope this helps

bdub
'76 Palm Beach
In The Heart o Texas
www.web-access.net/~bmassey/
icq # 202333
 
Billy,
Thanks so much for your response. Have printed your answer and will check
it out ASAP. Looks like we are in for some bad weather beginning tonight.
Neely
- -----Original Message-----
From: Billy Massey
To: gmcmotorhome ; GMC chat

Date: Monday, December 21, 1998 4:14 PM
Subject: Re: GMC: Working on "bugs"

>>The heat/AC blower motor will not run on high speed, OK on lower speeds.
Is
>>their a separate fuse for high speed? If so where.
>>Thanks.
>
>I can't find it but I think I remember someone saying that it ran right off
>a different source than the other speeds. not sure what that means.
>Mine wasn't working the other day and I wiggled the connector around on the
>heater box and it started working again. It's accessible through the
>drivers side front access panel, near the master cylinder.
>
>Hope this helps
>
>bdub
>'76 Palm Beach
>In The Heart o Texas
>www.web-access.net/~bmassey/
>icq # 202333
>
 
The fan relay, as previously described, is silver & looks like a horn relay. It
is mounted rather high up on the firewall on the passenger side. A #14 red
double white stripe wire goes to one of the terminals. There should be a 30 amp
fuse in-line with this wire. I have found that a single 30 amp fuse holder will
usually melt in time. Two 15 amp fuses in holders will last longer. Better
still, use a 30 amp circuit breaker. I have never had a problem with one of
those. Be sure to use a minimum #14 stranded wire for any rewiring you do.

One other item: the high speed fan operates only when the engine is running. It
receives its voltage directly from the alternator, NOT from the battery.
If you have to replace the relay, do NOT use a horn relay. A horn relay is a
single pole-single throw switch. The fan relay must be a single pole-double
throw switch or double pole-double throw. The normally closed position controls
all speeds except high, the energized or normally open position controls only
the high speed. One terminal for the coil must be isolated from ground to
receive 12 volts, the other terminal can be internally grounded or isolated from
ground and grounded externally.

> The heat/AC blower motor will not run on high speed, OK on lower speeds. Is
> their a separate fuse for high speed? If so where.
> Thanks.
> Neely B. Tenn
> '78 Eleganza
 
Neely:

Two possible reasons for no high speed fan: 1) contacts dirty in switch
(you'll need to wiggle and push etc.), or 2) you're testing without the
engine running (must be to get high speed).

BTDT, HTH

Dave Lowry, '76 Royale, Santa Barbara