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Pontiac Bonneville Rear Window Defrost

danthemandawgdanthemandawg Posts: 7
edited July 17 in Pontiac
My rear window defrost not working
I checked the 2 leads on right and left hand side of the back window and get 0 volts,(with car running and rear defrost button engaged)
the fuse is good,
and the light comes on when I push the botton (on the controll cluster display),
I have 99 Pont Bonneville, with climate controll, SSE, V6 no turbo 3.8 L
everthing else works, heat, air, front window defrost, just cant get rear to defog, the solder joints are good, and there are no breaks in lines o the window.
Is there a reley I can check, has anyone ran into a simular issue???
Thanks in advanced for all your help, this is driving me crazy

let me know if you need more information.
Thanks again
Dan

Comments

  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,196
    You have a small box about the size of a playing card pack on the passenger side C-pillar. Just pull out on it. There are two pins that friction fit into the metal behind it.

    The small connector serves as an antenna connector to take the antenna signal from the rear defrost grid and as a pass though for the power for the grid. You'll have to see if you're getting power there.

    Ahead of that is a relay of some kind. I do not know where it is located. If you have power measured compared to a ground back there, the relay up front isn't the problem.

    The connection at the little box are a friction fit and sometimes burn and corrode from the heat. You might try sanding them. Or look for a replacement box at a recycling yard.
  • Hey thanks for responding so fast
    , are talking about in the truck, passenger side, where my power antenna is???? look for a small box (as big as a playing card), check the wire connections to that box, there???
    I do have power to the Antenna because I can hear it go up and down when I start or stop the car.
    Now from what your saying, power from there should go to my rear defrost grid inside the car on both sides. In the back of my car I have both those covers riped off so I can see where the connection is coming in to the insides window defrost grid, its hard to follow those wires in the trunk, to figure out where they go. I didnt see what you were talking about ( passenger side C-pillar. Just pull out on it. There are two pins that friction fit into the metal behind it).

    Is the C-pillar in the trunk near the power antenna??? a part of the metal frame which is tough to see behind of.
    Also if the power antenna works your saying it cant be a relay then??
    Hey thanks again for all your help, this has been driving me crazy I will send pic if I can.
    Thanks
    Dan
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,196
    You have a power antenna?

    I didn't know they were available. When I ordered my H-body leSabre in 1998 (1997 DEC) they weren't offered, but apparently were on a Bonneville unless someone installed it aftermarket. I learned something from your post!

    In that case you do not have the separator box (whatever the right name is) to pick up the radio signal off the antenna wires.

    Do you get voltage to either side of the grid with one end of the meter connected to a ground (bare metal on the C-pillar?)?

    Now I had to go get my 98 service manual for Olds/Pont/Buic.

    Your relay is on the right-hand instrument panel board. That's up under the passenger side against the A-pillar area. Take off the hush panel above the passenger legs. on top of the hush panel will be a diagram of that fuse/relay board.

    There might, might be another relay on the board that has the same part number. Under the hood in the relay center on the firewall many of those are the same relay as others in that area, so maybe you can switch relays to test.

    BUT FIRST check your fuses.
    This is confusing but power to the relay pull on comes through a 15 A Auto/AC/Cruise fuse in the driver fuse block--row 5 column A

    Power to the relay secondary ciruit to pulls it to the on position comes through a 30 A fuse name RR DEFOG in row 5 column E

    A second ciruit page shows BASE AC fuse of 25 A in row 5 column "0" in instrument panel fuse block. Not sure which column it is, look for a 25 A.

    I'd check fuses first... BTW one of these may be for the standard AC and the other for the auto control AC. That might be the "base" in base AC.
  • This is the first thing I checked,
    Power to the relay secondary circuit to pulls it to the on position comes through a 30 A fuse name RR DEFOG in row 5 column E

    I will double check this one
    A second circuit page shows BASE AC fuse of 25 A in row 5 column "0" in instrument panel fuse block. Not sure which column it is, look for a 25 A.

    first thing I did was check the fuses, under driver side, passenger side, and under the hood near the fire wall, all were good, verified with meter to be certain.

    I get 0 volts when I turn on the rear defrost with the car running and my meter touching the bare solder connector, on both sides of the window (on my car there are two points where power comes in to the inner defrost wires).

    my ac, cruise control, everything else is working fine. but my power antenna is bent really bad so I'm not certain if that is still working or not, I will check it out.
    under the hood there is a set of 4 relays, wondering if maybe one of those are bad?? they are not marked on the black plastic, nor in the owners manual, or in my chiltons book.(for some reason my chiltons book has that page 12-8 whited out so you cant read it, oh how luck am I).

    Its hard to follow the wires in the trunk for the defrost, but will check to see if I'M getting any voltage there.

    From what I'm reading you turn on the rear defrost (i have the climate control system) it goes thru a fuse, energizes a relay, than goes to the wires on your window.
    Is there any known issues I'm not aware of, worse case I'm going to splice my power antenna wires, hook up a toggle switch to the rear defrost if I have to. Live in Central Ohio, have to have it.

    Thanks again for every ones help
    Dan
    I'm going to take some pics and post so everyone can see what I'm talking about, sucks it gets dare a 5:30, I have no garage to work in anymore.
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,196
    This is the Relay Center under the hood (and fuse center).

    image

    For the relay check to the rear window, that's on the passenger side. Cobble up a pair of wires with a fuse in the middle and connect it into the holes for the relay that are the secondary, main, circuit powering the rear defroster. OR use a meter to see if you get power on one of the two main contacts when the key is ON and the Defrost is energized at the switch. Be sure to use a known ground to check. :)

    Although the passenger side fuse/relay center is a little hard to get to, it was fairly easy when I was checking my circuit for the auto-leveling air system for the rear struts.
  • imidazol97
    Thanks for pics
    ok, my relay center under the hood, i only have 4 relays,
    are you talking about inside the car, passenger side, look for the relay and fuse their???
    I have already checked the driver side, i believe its 5E, didnt realize i had more fuses and relays to check inside the car on the passenger side, When I have some light I will check it out and let you know, man I hope its as simple as that.
    Hey do you know where I can find some information on an manual on the Bonnevilles, I have a Chiltons, but some of the pages are whited out, the one I need, and I cant read it.
    Thanks again
    Dan
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,196
    >Now I had to go get my 98 service manual for Olds/Pont/Buic. ;)

    "Your relay is on the right-hand instrument panel board. That's up under the passenger side against the A-pillar area. Take off the hush panel above the passenger legs. on top of the hush panel will be a diagram of that fuse/relay board. "

    Your relay center will not have all the fuses and relays, depending on options on your vehicle.
    When you take off the passenger hush panel under the dash, you'll see a picture on top of the layout of your specific little relay panel inside the car on the passenger's right side.
    My guess is that the electronic level control relay will be the same part number as the defroster so you might switch them to see if the relay is the problem. They both would be handling a good current load compared to other circuits. But the relays may all be the same.
    If the ELC works, switch that relay in and see if the defroster now works or at least gets power to one side of the rear window relative to a ground on the metal of the car.

    image
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,196
    Manuals for car????
    You're in luck.

    The best thing is a factory service manual printed for GM to sell in the last page on the owner glovebox manual. It's published by Helminc.com for many auto company brands. Here's a 99 Bonneville two-volume set two-volume set from a defunct dealership, based on a quick read. I'd jump on it. $24 + $9 shipping = $33. I have bought manuals from Helm for most cars since my '67 Mustang. The Chilton's and Motors were too generic and worthless dollarwise. The '99 manual is probably listed new on the helmin.com for $135 plus shipping plus handling. To find manuals on Ebay click on the link above or search ebay with "factory service manual bonneville."

    Make sure you read description and get all the volumes of manuals for a particular year. Often people are selling one volume instead of the whole set. My 98 Buick is 3 volumes, but it covered Olds Buick Bonneville. It looks like the 99 was a two-volume set, as I see it. Realize dealerships went to digital service manuals about that time, so the paper copies were purchased instead of paper. The ebay lists a 97, 98, 99 for Bonneville being liquidated.

    It sounds like you do a lot with your car repair. You'll be glad you have the actual manual with wire colors, prong location on connectors, etc. Compared to chilton's for $20, this is a steal. The manual makes great reading material for things you don't work on but just to understand how they are set up and wired.
  • Keith
    Thanks for everything I greatly appreciate it. I was raised to fix things myself, I never saw my father hire a mechanic, handyman, or anyone of that nature, we fixed it ourselves and saved the money.

    Ok with the rear defrost, I found it (the relay) on the passenger side, way up on the right hand side, had to recline the seat back, lay down backwards, and still almost couldn't grab it. I was able to pull out the relay, and it was bad, replaced, works just fine, again I wouldn't have found it with out your help :shades:

    I will defininently jump on that factory manual tonight, I'm sick of Chiltons generic black and white, back yard mechanic crap with pages you cant even read.

    My next project is to figure out why the car is hesitating (when I'm accelerating, sitting Idle, or running the cruise control at 70mph) I have done all the routine maintanence, plugs, wires, new fuel injector, o2 sensors, map sensors, you know what I mean. Its burning about a quart of oil every 2 weeks, no leaks though. I see excessive smoke coming out of the exhaust. I thought for sure it was the valve seals, I replaced em, helped a little bit. but the issue is getting worst now. It starts fine, runs, I just feel a little hesitation (sputter, buck, every couple of cycles) and I could hear a pinging sound (it sounded like it was coming from the exhaust, not a piston ring). I want to get this taken care of before I blow the motor.
    Hey thanks again for all your help
    Dan
  • I have a 93 bonneville and i cant get the ac to work the relay is good i can jump the compresser off the batt and make it run and blow cold air but i cant get the compresser to run by its self if i try and jump the high pressure switch nothing happens if i jump the low oil switch nothing happens what do i do next
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