1980 Jeep CJ-7

Blower Motor Upgrade

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As most of you know, I bought an old jeep last February. 

Specs: 1980 CJ-7 AMC 360 V8 Automatic Transmission

I’ve replaced almost everything on the jeep.  With hunting season around the corner, I thought I’d update you on some of the mods I’ve made on the jeep.

These old jeep are notorious for having poor heat flow – takes forever to get the cabin warm and windows defrosted.  There’s lots of forums on the internet concerning jeep modifications.  One of the more popular mod is the heater motor upgrade.

Basically – replace the small jeep blower motor with a larger blower motor from a 1973 Chevrolet Blazer.  The bolt pattern and mounting is identical.  The motor housing is larger so you must cut a larger hole in the firewall.

Bought the new motor at Advance Auto Parts for $20.

First step is to remove the Fresh Air/Heater housing from inside the jeep.  There’s 4 studs on the housing that protrude trough the firewall.  Take the 4 nuts off and disconnect the two holes to the heater core.  Also, disconnect the drain hose.  Have a 5 gallon bucket ready – when you disconnect the heater hose water/anti-freeze will come roaring out.

The assembly will slide out with some wiggling and pressure.

Take the 14-16 screws out of the back of housing and it will come apart.

Take the 8-10 screws out holding the blower motor in place, take the one nut holding the fan blade in place.

Replace the motor and reassemble.  I elected to clean everything up and paint it.

Everything is mechanical on the heater except the motor itself – cables control the vents with pull/push levers on the dash.

It wasn’t a bad job – toughest part was cutting larger hole in firewall and getting bolts/screws out – everything is tough to get loose on a 30 year old jeep!

It’s working great – got 3-4 times the air flow from before!

This is a picture from March – been a lot of changes since then.



Heater housing assembly - fits under dash – that’s the heater core in picture


Old motor on left new motor on right - much larger with higher air volume – they have the same outer flange and bolt pattern



Back panel of heater box - this connects to the firewall from the inside - the 4 bolts go through the firewall and connect in the engine compartment.


Inside of heater box back


Heater box reassembled and ready to install - everything cleaned. primed and painted - new motor installed.

The picture is exactly how it fits in jeep – the pipe below motor is for a drain hose for any condensation or leak from heater core –

The two brass pipes connect to heater core – one for water going in and one for water returning to radiator –

The 4 studs (top left, right side of motor, above heat core and far right) stick through holes in the firewall – a nut is

Installed on them to hold heater box in place – that’s the old motor on right – big difference in size


Inside of firewall where battery was located


New Motor has a larger housing - had to cut larger hole in firewall for motor


repaired broken heat vent with super glue an electrical tape


Front view with new motor in place and fan installed - put new foam insulation for cover


Front with vent housing installed



Complete housing – everything painted – this view is from the top – the vent on the left is covering the

Motor and fan housing – fresh air comes in from the vent at the back of the hood – the opening on the

Right is where air goes out to the defroster – it pretty simple – turn the blower on – fresh air comes in on

The left – the blower blows the air over the heater coil – hot air is blow out the bottom by feet and/or defroster

Depending on which vents are open.




Under dash with heater housing removed – you can see hole where blower motor fits through the firewall


Hole cut and new motor install - the heater box is inside the vehicle and installed - the electrical wire is attached

to the motor - the drain line is through the fire wall - the bolt on top left is one of four that bolts the heater box to the firewall


Battery tray sanded and hand painted with Rustoleum Rust Preventer


Battery tray primed


Battery tray painted black


Battery tray installed


Top on new battery box trimmed to fit - this will keep water off the top of battery from hood vents


Battery tray and battery installed - you can see new motor at bottom left of battery tray


Top in place


Heater control knobs



Lower vent – hot air can be blower from here and/or the defroster


Blower cover in place – fan blades behind vent door that is open – it can opened to allow fresh air in during warm months

Needs some touch up painting


Heater core lines attached


Finished unit and everything working great – radio is out for another project



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