Fan blower don't work on high !

[gnxparts]

So Is there a resistor ? And where is it located ?
Thanks

 

[chopped39]

There is a resistor under the hood and the high blower relay is mounted right by it . They are on the hvac housing

 

[gnxparts]

Is that part replaceable and from where ?

 

[chopped39]

Is that part replaceable and from where ?

Im sure highwaystars, Gbodyparts or kirbans would have it. Napa shows part numbers echbr25 for resistor $13.00 and mpear203sb $12.00

 

[John Larkin]

It's the relay. You can either buy a replacement or open yours up and drag a little sandpaper through the contacts on both sides. That may work, did for me.

 

[larry33kc]

Check the plug down by the pass. fender. Turn the fan on high and wiggle the plug. That's what it was on mine.

 

[robzombie]

X2 on what is said above by others.

Take out the relay after you find it, and then check the harness/plug to check for any signs of corrosion and or over heating. If the plug isn't melted or burnt just do as the others have posted and clean all contacts in the plug as well as on the relay to make sure you have optimal contact. If not totally clean from all carbon build up or corrosion it will cause higher resistance that can and will melt the connector.

All G bodies of that era are prone to this and I've seen my share of melted harnesses because of this problem.

Once cleaned use some diaelectric grease to prevent the corrosion from water and moisture that causes this problem in the first place.

 

[huntsg]

I have the same issue. Just to be clear, both of these are located on the blower box? One is kind of a rectangular box and the the other has the spiral wire coil that you can see when you pull it out?


'87 GN 58K miles (rebuilt engine by Don Cruz at 47K), 6262 Billet Precision Turbo, Precision 60 lbs injectors, 206/210 Revolution X Roller Cam, Comp Roller lifters, Champion Iron Heads, Champion Ported Intake, T&D 1.65 Roller Rockers, 70 mm Hemco Upper Intake, 70 mm Acufab TB, PTC 10" TC 2800 Stall w/LU, Razor's Kit, ESP FMIC, B & M Shift kit, 3" GN1 DP w/46mm external wastegate, 2 3/4" Dual Magna flow exhaust, ATR Headers, 3.5" Kirbans Aluminium Driveshaft, Eibach Pro Kit Springs, Bilstein Shocks, Spohn Boxed Rear Lowers, Spohn Rear Uppers, SD2 Chip, XP Plus Fuel Pump w/hotwire, Turbonetics Boost Controller, Scanmaster, Powerlogger, Hurst Line Lock, MT ET Streets 255/50-16

 

[novaderrik]

the resister has nothing to do with the high speed fan- it just provides different levels of resistance for the slower speeds.. so if the other speeds work, ignore it.
the relay is what provides power directly from the battery to the motor for high speed.

 

[larry33kc]

Go and check the plug. I just erased the pic of it from my phone yesterday. It's by the power plug for the antenna, down behind the fender skirt, AC box. I think it has two wires into it and one of them is a larger red wire.
With the fan on high and key on wiggle the wires and plug and it probably will come on. If not then it might be the circuit board and it high $.
I have see people cut the plug out and crimp the wires together.

 

[gnxparts]

Great Idea I will check that out ASAP

 

[huntsg]

I checked the relay and it seems fine (I switched it out with one from another car). I found the plug. It has 3 wires coming out of it. The red and light blue go in the wire loom but the black is loose and not connected to anything. Is it a ground and should it be connected?


'87 GN 58K miles (rebuilt engine by Don Cruz at 47K), 6262 Billet Precision Turbo, Precision 60 lbs injectors, 206/210 Revolution X Roller Cam, Comp Roller lifters, Champion Iron Heads, Champion Ported Intake, T&D 1.65 Roller Rockers, 70 mm Hemco Upper Intake, 70 mm Acufab TB, PTC 10" TC 2800 Stall w/LU, Razor's Kit, ESP FMIC, B & M Shift kit, 3" GN1 DP w/46mm external wastegate, 2 3/4" Dual Magna flow exhaust, ATR Headers, 3.5" Kirbans Aluminium Driveshaft, Eibach Pro Kit Springs, Bilstein Shocks, Spohn Boxed Rear Lowers, Spohn Rear Uppers, SD2 Chip, XP Plus Fuel Pump w/hotwire, Turbonetics Boost Controller, Scanmaster, Powerlogger, Hurst Line Lock, MT ET Streets 255/50-16

 

[huntsg]

Also, I just charged the ac system and it's only blowing out the defrost vents.


'87 GN 58K miles (rebuilt engine by Don Cruz at 47K), 6262 Billet Precision Turbo, Precision 60 lbs injectors, 206/210 Revolution X Roller Cam, Comp Roller lifters, Champion Iron Heads, Champion Ported Intake, T&D 1.65 Roller Rockers, 70 mm Hemco Upper Intake, 70 mm Acufab TB, PTC 10" TC 2800 Stall w/LU, Razor's Kit, ESP FMIC, B & M Shift kit, 3" GN1 DP w/46mm external wastegate, 2 3/4" Dual Magna flow exhaust, ATR Headers, 3.5" Kirbans Aluminium Driveshaft, Eibach Pro Kit Springs, Bilstein Shocks, Spohn Boxed Rear Lowers, Spohn Rear Uppers, SD2 Chip, XP Plus Fuel Pump w/hotwire, Turbonetics Boost Controller, Scanmaster, Powerlogger, Hurst Line Lock, MT ET Streets 255/50-16

 

[salvageV6]

Red wire provides the power, it is live at all times so test it with a voltmeter on both sides of the connector or start at the relay and work your way back.`

If the blower motor works on the other speeds it's not the ground, there's only one off the blower motor itself black wire.

Make sure the relay turns on with the high speed setting, orange wire on the relay is the trigger and should read +12 to a good ground with a meter when the blower switch is on HIGH, key ON test.

 

[larry33kc]

That's the pic I deleted yesterday. That's what you look for. I had a dad connection there

 

[chopped39]

Also, I just charged the ac system and it's only blowing out the defrost vents.


'87 GN 58K miles (rebuilt engine by Don Cruz at 47K), 6262 Billet Precision Turbo, Precision 60 lbs injectors, 206/210 Revolution X Roller Cam, Comp Roller lifters, Champion Iron Heads, Champion Ported Intake, T&D 1.65 Roller Rockers, 70 mm Hemco Upper Intake, 70 mm Acufab TB, PTC 10" TC 2800 Stall w/LU, Razor's Kit, ESP FMIC, B & M Shift kit, 3" GN1 DP w/46mm external wastegate, 2 3/4" Dual Magna flow exhaust, ATR Headers, 3.5" Kirbans Aluminium Driveshaft, Eibach Pro Kit Springs, Bilstein Shocks, Spohn Boxed Rear Lowers, Spohn Rear Uppers, SD2 Chip, XP Plus Fuel Pump w/hotwire, Turbonetics Boost Controller, Scanmaster, Powerlogger, Hurst Line Lock, MT ET Streets 255/50-16

There is a vacuum line coming out from under the heater box.Its either black or gray I cant remember but that has to go to a vacuum source on the engine

 

[huntsg]

Here is how my problems worked out. The reason the fan wouldn't go on high speed was in fact due to the connector on the passenger side fender well near the blower motor. The connector was melted and wouldn't separate so I had to cut the red wire. Of course in typical GM fashion there wasn't enough wire to work with so I had to solder on a short extension and then connect them back together, bypassing the connector. The problem with it only blowing out the defrost vents was fixed by pulling out the head control unit from the dash and pushing in all the vacuum lines on the back. Thanks for all the help.

 

[larry33kc]

Glad you got it figured out.

 

[X Ray]

Also, I just charged the ac system and it's only blowing out the defrost vents.


'87 GN 58K miles (rebuilt engine by Don Cruz at 47K), 6262 Billet Precision Turbo, Precision 60 lbs injectors, 206/210 Revolution X Roller Cam, Comp Roller lifters, Champion Iron Heads, Champion Ported Intake, T&D 1.65 Roller Rockers, 70 mm Hemco Upper Intake, 70 mm Acufab TB, PTC 10" TC 2800 Stall w/LU, Razor's Kit, ESP FMIC, B & M Shift kit, 3" GN1 DP w/46mm external wastegate, 2 3/4" Dual Magna flow exhaust, ATR Headers, 3.5" Kirbans Aluminium Driveshaft, Eibach Pro Kit Springs, Bilstein Shocks, Spohn Boxed Rear Lowers, Spohn Rear Uppers, SD2 Chip, XP Plus Fuel Pump w/hotwire, Turbonetics Boost Controller, Scanmaster, Powerlogger, Hurst Line Lock, MT ET Streets 255/50-16

The defroster vent is the default when the Climate Control Vacuum Valve goes bad ..... ACDelco part number 15-71389 or equivalent will fix this.