Help with rear defoster

[Q45denver]

Anyone know if the rear defroster is tied into the BCM? The one on my 95 Q is not working and apparently it is not a continuity problem or a problem with the switch itself. Maybe I could hard-wire it directly to the switch?

[morsecode]

Have you checked for any breaks in the line? Grid lines can be easily damaged, so there may be a problem there.

The rear defroster is tied to the BCM through an output line that connects to the coil of the rear window defogger relay.

[Q45denver]

Have you checked for any breaks in the line? Grid lines can be easily damaged, so there may be a problem there.

The rear defroster is tied to the BCM through an output line that connects to the coil of the rear window defogger relay.

Yes, I did a continuity test and replaced the switch, I'll also try replacing the relay with a know good one. What would I need to check the BCM? A Nissan Consult?

[morsecode]

Usually, I don't check the BCM unless a lot of stuff connected to it like the wipers or door locks won't work. But you can send your car to a shop and have them run a scan to check if there are trouble codes in the BCM.

[Q45denver]

Ok, thanks. Hate to take it to the dealer because they always seem to find a way to screw me and this is currently the only thing on the car not working.

[Infinitiguy19]

Well if you like to read and have a Volt meter your in luck, There should be a way to test the pins on the BCM responsible for the defroster to see if the receive power.

I wish that the dealer would loan those Consult's out, I would gladly leave my sister truck with them.

[Q45denver]

I had a spare BCM for awhile that I think I sold to Texoil. I swapped it out with a BCM in another 1995 that didn't have any instrument display but it didn't make any difference. They are in a awkward location and a pain to get at. I'll try the relay and then probably take it to the dealer. At least they still give loaners (I think)?

[goody90q45]

I didn't see you mention checking the pair of fuses in the passenger compartment fuse box. Is the switch's light coming on when you depress the on/off button?

........They are in an awkward location and a pain to get at. I'll try the relay and then........?

You probably already know this but you're looking for a brown relay above/behind the TCU. It can be swapped with another brown standardized relay to test it. It looks like there's a couple in the engine compartment fuse box. See EL-239 and 240 in the FSM for more detail.

[Q451990]

I need to get out more... maybe read a book sometimes or something! How sad is it that I can tell the blue relay at 5:00 in your picture is probably the audio relay removed from behind the ECU due to the black foam residue?

Heath

[Denver90Q]

Yes, the switch light comes on and fuses check out ok. Do you have to remove the TCU to see/ remove the relay? I did remove the TCU access panel but I could not find the relay.

[goody90q45]

IIRC it's behind the piece of foam which may or may not be covered by the TCU. Peel the foam back and you'll see a cluster of relays mounted to one bracket.

Once you find the cluster unscrew the bracket from the chassis and pull the cluster out a few inches rather than trying to reach your paws in the cavity and unplug one relay.

[goody90q45]

I need to get out more... maybe read a book sometimes or something! How sad is it that I can tell the blue relay at 5:00 in your picture is probably the audio relay removed from behind the ECU due to the black foam residue? Heath

The only cure to our ailment is to get rid of everything Infiniti related, buy a new Nissan Versa and forget our NICO password. I blame Wes.

[Denver90Q]

Thanks, Took it to the dealer but they couldn't figure out what was wrong with the defroster either. At least it's probably not the BCM as that should have shown up on the Consult.