Replacing the Antenna Base in a 2nd Generation Prius

     If you've broken the base of your Prius antenna by backing it into your descending garage door, you've come to the right place.  My antenna mast was fine, but it was dangling by a thread (well, by a wire) from the black cone that supports it.  The cone is called the "antenna base".  It contains a small pre-amplifier and sells for between $200 and $300.

    Lesson One: don't break the antenna base.

    My friendly Toyota dealer said it would cost close to $1,000 (!!!) to repair this: $283 for the antenna base and the rest for labor... he said it was a "labor-intensive" job.  That works out to almost a full-day of labor at $100/hour, and assumes there's no sheet metal or paint damage.  (These prices were in the Summer of 2009.  The dealer really is friendly and I do trust them, but they're using "book estimates.")

    In fact, anyone who has done this once could do it again in about 30 minutes.  It took me about 2-1/2 hours, most of which was spent taking the photos you'll find below, and figuring out how to loosen three things without breaking them.

DISCLAIMER:   Make this repair at your own risk.  If you aren't sure you can do it without hurting yourself or your car, take it to the shop.

YOU WILL NEED:  A new antenna base, which comes with a 2' cable and connectors.  In August, 2009, the dealer wanted $283, but on the Web, it was about $200 (plus tax/shipping) from various Toyota Parts suppliers.  I got mine from City Toyota Parts in South San Francisco, and it arrived by UPS 2 days after I ordered it.  It looks like this:


    If you've broken the antenna mast, you'll need one of those, too.  In fact, if the mast is broken, the base may be OK, so try a new mast first.  It costs much less than the base.  Maybe a friend with a Prius will let you try his mast for a few minutes.


    Tools needed:


   OK, let's get started.  Here are close-ups of parts of that antenna base:

Retainer clip.  Holds wiring to roof of car


Black plug, goes into black socket above rear right seat


White plug, goes into white socket above rear right seat.
Note the thin flange on the top.  It actually faces the right
side of the car when installed, and must be squeezed to
remove it.  It took me an hour to figure this out.


Underside of the antenna base, next to 22mm nut that threads
onto it.  Note the spring clip inside the nut.  It goes into the
groove that runs through the bolt.  Also note the square black
gasket in the middle of the base, surrounding the
threaded bolt.  That gasket is what keeps water out of
the car.


Base with nut attached.  This is just for illustration.  In real-life,
the base is on the roof, it's bolt and wires are pushed through
a square hole in the roof, and the nut is inside, under the roof.


Close-up of nut: bottom view


Close-up of nut, top view.  Note the groove on the lower-left.
The wires must run through it so they don't get pinched.


Pre-amplifier circuit board inside the base.  If you're replacing
the base, you do not need to open it.  This is my old, broken
base (a component broke off and a black wire from the
board to the top-nut that holds the antenna mast is missing.)
This illustration has nothing to do with the job; it's just to
satisfy your curiosity.


STEP 1: Partly remove the rear light fixture.  I'm not sure this is absolutely necessary, but it seemed like the safe thing to do.  I sat in the rear-right seat for this.  The front-right and rear-left corners are easy to pry out; the other two corners are very difficult to pry out.  You want to pull down the right side of the light, without breaking the hooks that hold it in place, then easily pull out the left side.


The light, in its proper place


That's a VERY small, thin screwdriver.  You can pry this
corner out easily from its front or its side, but only
enough to dislodge it, as shown.  It won't go further.


This hook holding this corner is hard to dislodge.  It's actually a
little to the left (towards the rear of the car) of the screwdriver.
Use the screwdriver to push its flexible tab inward, to bend
the hook, and pry down to dislodge it.  Be careful here.
A later photo will show the hook in detail.


The right side of the light is dislodged from the roof.


Here's a side view of that hook.


The screwdriver is pointing to the lever that must be pressed
to free the hook.  Looking at these photos, you can see that
this hook is a lot bigger & thicker than the other one.


STEP 2:  Remove the three "headliner plugs" that secure the headliner to the top-rear of the passenger compartment.  Until getting into this job, I didn't know what a "headliner" was (except in the entertainment business).  It's the material that covers the inside roof of the car... and it probably can break if you're not careful.  I did this, and everything else that follows, from the cargo bay.  NOTE: apparently, the early 2nd Gen Prius didn't use headliner plugs.  If your car doesn't have them, skip to step 3.


Those are the three "headliner plugs".  (Behind them, the light is
dangling from Step 1.)  You'll need to pull those plugs without
breaking them or marring the fabric of the headliner.
For each plug, I slid a thin metal shim into one side of its head,
then another shim into the other side, and pried each one out.
Put these plugs where you'll find them later on.


This is a headliner plug.


Here's the back of the headliner with the plugs removed.


STEP 3:  Pull the headliner out from the moulding along the back and sides of the car, until you reach the ceiling handles.  Do this with your fingers, starting in the middle, where the screwdriver in the next illustration is positioned.  Work slowly and carefully to avoid creasing or breaking the headliner.


The left back corner of the headliner has been pulled out.
Work forward about a foot or more, until you get to the
ceiling handle, then repeat on the right side.
The two sides are NOT symmetrical.


The loosened headliner has been pulled down.  I used the
headrests to hold it down, as it wanted to spring back up.


STEP 4: Remove the 22mm. nut that secures the antenna base through the roof (easy); remove the retaining clip (easy); pull out the black plug (easy); release and pull out the white plug (easy once you know how; it took me almost an hour to figure it out).


Wiring under the roof.  Details shown below.  You can see the
22mm nut with a black wire coming out of it just left of center,
the white retaining clip along the black diagonal wire,
and the white & black plugs near the right side.  They'll be
easier to see in the detail photos below; this is just to give
you an overall view of what's where.


The 22mm nut and the bolt from the base.  They're right under
the antenna, of course, dead center.  Use the 22mm socket
wrench or a crescent wrench to loosen and remove the nut.
Put the nut where you will find it later on.


The nut again, and the wire leading to the white retaining clip.


Pull the retaining clip down, out of the hole in bracket.  You can
pry it out with a screwdriver; it isn't especially fragile.


The retaining clip has been removed.  The one on the new
antenna base will be pushed back into the same hole
in the bracket (the forward hole).


The white and black plugs, in place on the right side.


The black plug just pulls out, easy as pie.
The white one does too, if you squeeze that lever
next to the arrow, and pull while squeezing.


The empty sockets.  Now, you can carefully pull the antenna base
off the roof (wiggle and twist it back and forth) and extract the
wires you've just disconnected.


STEP 5:  This is the mid-point of the job, but you're 80% finished; all you have to do is install the new antenna mast and put things back together; and that is a LOT quicker & easier than taking everything apart.


Drop the wiring of the new antenna base through the hole in the roof.


Seat the antenna base on the roof.  Remember that it points
towards the back of the car.  It'll be necessary to gently
twist and wiggle it to get it in.  Try not to bend the copper
"ears" on either side.  If you do bend them, you can
press them back gently with pliers.


From inside the cargo bay, you can see the bolt of the base.  The
wire should be facing the rear of the car, and will have to be bent
up towards the roof to make room for attaching the 22mm nut.
If the base slips upward, you may not be able to thread the
nut in place.  Either ask someone to hold the base in place,
or put something soft and heavy on it.  (I used a lunch cooler.)

Place the nut onto the bolt of the base, with the hex part facing
downward and the spring clip facing the back of the car,
so that the clip slips into the grove of the bolt.
Hand-tighten the 22mm nut onto the base.  If it doesn't go on
easily, it's not threading correctly.
Once you've got it on correctly and as tight as it can go,
you should see some of the threading sticking out past the nut.
Make sure the external part of the base is in-line with the car, not twisted.
Finally, use the 22mm socket or the crescent wrench to tighten it
enough to ensure the square gasket forms a water-tight seal.

Push the white and black plugs into their sockets.  Remember
that the lever on the white plug goes on the right-hand side.
Make sure both plugs are fully inserted.

Push the retaining clip into the front hole of the bracket.


STEP 6:  Re-attach the antenna mast to the antenna base.

STEP 7:  Turn on the car, turn on the radio, and make sure you have normal reception on AM and FM.  Do this before putting the headliner back in place.  If you don't have normal reception, check the connections.  If it still doesn't work, make sure the antenna mast wasn't damaged.  Since my "repair" was successful, I have no ideas about what to do if things aren't working properly at this point.

STEP 8:   Carefully push the headliner back into place with your fingers.  Start at one side, under the ceiling handle, and slightly bend & push the edge a little at a time, working your way back to the corner.  Then do the other side.  Go inside the cabin and look at the headliner to make sure it's all back in place properly.

STEP 9:   Push the headliner plugs back into their holes.

STEP 10: Push the light back in place by seating the left side first, then pushing up the right side, and pressing until the hooks click back in place.

STEP 11:  There is no step 11; you're done, and you saved almost $800.


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