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Discussion Starter #1
I have no brakes, none light up. All the bulbs are ok.
I have power at pin 2 on H3 at the brake light switch.
I've tested the switch itself and it works as it should with the pedal both up and depressed.
The fuse, F15 is OK.

This is quickly getting narrowed down to the brake control unit, or the relay. I believe the relay is behind the instrument cluster, right? Which one?

It looks like the control unit is with the rest of the computers under the radio. Which one?

It may be easier for me to swap out the control unit with a spare I have than take the instrument cluster out. I'm not sure what the brake control unit looks like. Is the B/L control unit the same as the S?
 

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Bro I had that happen to me 4 times already and its not the computer,bulbs,fuses. Its the Black Relay outside in the wire cluster by 40amp fuse box under driver side wiper. That relay is exposed to all the elements the main one being water. Its because when it rains or wash your car or snow melts the first place the water runs to is the wire clusters..you would think why would ALFA install the wire clusters in a place where they are exposed to all the elements BTW while you are in there clean up all those leaves, dirt, acorns,sticks. Water is what creates a short within the relay itself causing the computer to "THINK" that the bulbs are shot. A heads up bro The best thing to do is to melt candle wax on it and make it water proof. I would do the same to the screw off clusters too. Just enough wax around the seams of the female and male cluster. OH YEA!! before you screw the cluster together the male and female part stuff some dielectric grease in there!! then screw it back together and wax it all around. Hope this helped.. Ive had this happen to me 4 times already it happens more in the winter simply because snow sits under the wipers and as it melts the water somehow finds its way to the relay . Heck all you got to do is just press and hold your brake pedal for like a minute strait and go to the relay and feel it and if I'm not wrong it should be warm if it hasn't shorted out completely already.
 

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I have no brakes, none light up. All the bulbs are ok.
I have power at pin 2 on H3 at the brake light switch.
I've tested the switch itself and it works as it should with the pedal both up and depressed.
The fuse, F15 is OK.

This is quickly getting narrowed down to the brake control unit, or the relay. I believe the relay is behind the instrument cluster, right? Which one?

It looks like the control unit is with the rest of the computers under the radio. Which one?

It may be easier for me to swap out the control unit with a spare I have than take the instrument cluster out. I'm not sure what the brake control unit looks like. Is the B/L control unit the same as the S?

As Danny says brake relay behind false firewall and if original actually bolted to back side of it near where a/c and heater hoses are located.

Rear lamps control unit and alfa romeo control unit both under glove box.
 

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Discussion Starter #4
Thanks for the replies. I guess I posted too soon. After all the testing, etc the brakes lights didn't work. Went I went to use the car half hour latter, they are working again. Maybe the computer had to reset or something. I don't know. Anyway thy are good now.
 

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Stop Lamp Control unit will fail intermittently. If the turn indicators work and the brake lights don't (they use the same filament inthe twin filament bulb) then suspect your stop lamp control unit (called the rear lamp control unit in the shop manual), under the glovebox. Also, if the lights start working again after you thump the control unit then that is the culprit.
 

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New 164S owner with an inherited brake light problem

Added a 1993 164S to my collection of 2 Alfa spiders. I figured it was time to have a manly sized car. Problem (one of a few), the brake lights do not come on. Instead I get the 'Brake' lamp and the 'Taillight' lamp on the dash turn on when I hit the brakes.
So I have checked H3 (it operates normally), replaced the relay in the false firewall with a known good unit, replaced the Alfa Romeo Control Unit (N22) under the dash with a supposed good one, checked the bulbs and the fuse.
Still no brake lights. I hear the relay in the false firewall click when I press the brake.
The only thing left is the Rear Lamps Control Unit (N44) but I do not know how to recognize it. I've read that it's located in the glovebox area but that is all I know. What does it look like?

Any other helpful test points would be greatly appreciated
 

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Added a 1993 164S to my collection of 2 Alfa spiders. I figured it was time to have a manly sized car. Problem (one of a few), the brake lights do not come on. Instead I get the 'Brake' lamp and the 'Taillight' lamp on the dash turn on when I hit the brakes.
So I have checked H3 (it operates normally), replaced the relay in the false firewall with a known good unit, replaced the Alfa Romeo Control Unit (N22) under the dash with a supposed good one, checked the bulbs and the fuse.
Still no brake lights. I hear the relay in the false firewall click when I press the brake.
The only thing left is the Rear Lamps Control Unit (N44) but I do not know how to recognize it. I've read that it's located in the glovebox area but that is all I know. What does it look like?

Any other helpful test points would be greatly appreciated
White box under glove box. #3
Very common failure item.
 

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One more query

Thanks for the reply.

#1 looks familiar (That's the Control Unit right?)

I do not recall seeing anything like #3, certainly not attached to #1 by that bracket. I guess I have to look harder elsewhere.

Do you know where I might be able to buy a replacement for #3 to give it a try?

B
 

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Would I be looking for the stop lamp unit under the glove box as well if if the center and passenger side (right) brake lights work but the drivers side don't? Replaced bulb w/no change.
 

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Would I be looking for the stop lamp unit under the glove box as well if if the center and passenger side (right) brake lights work but the drivers side don't? Replaced bulb w/no change.
I would be testing ltblu-red wires to left brake light bosch connectors at left rear tail light for 12v when brake pedal pressed. Also check that the black wires in connectors read to chassis ground. There are two bulbs in each tail light.


Rear lamps control unit N44 (unit 3 above) is mounted to a bracket that is mounted with two screws on each side of foot well light under glove box. Just remove those two screws and bracket and N44 will come out. Unit 1 is N22 ARCU and bracket 2 holds it not N44. N44 has it's own bracket so above parts CD/eper DVD picture is wrong as is shop manual on how it is mounted.
 

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Repair or replace

Does anyone repair either N44 or N22?
If not, where can you get replacements?

B
 

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Added a 1993 164S to my collection of 2 Alfa spiders. I figured it was time to have a manly sized car. Problem (one of a few), the brake lights do not come on. Instead I get the 'Brake' lamp and the 'Taillight' lamp on the dash turn on when I hit the brakes.
So I have checked H3 (it operates normally), replaced the relay in the false firewall with a known good unit, replaced the Alfa Romeo Control Unit (N22) under the dash with a supposed good one, checked the bulbs and the fuse.
Still no brake lights. I hear the relay in the false firewall click when I press the brake.
The only thing left is the Rear Lamps Control Unit (N44) but I do not know how to recognize it. I've read that it's located in the glovebox area but that is all I know. What does it look like?

Any other helpful test points would be greatly appreciated
Do you get third brake light to work? It works off N22 not N44 so check for 12v at white-red wire going to third brake light in trunk lid on 164S and rear window light on 164B/L.

Also there is a trailer provision white-red wire under battery cover that bypasses both N22 and N44 and relay I69. This wire comes directly from pedal switch H3. Check it for 12v too when pedal pushed.
 

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I have also had a helluva time with brake lights! This is the first time I have seen a diagram about the actual view of N22. Now about how to test it.....and where to get another?
 

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N22 control unit connections were my issue

My '93 L has had periodic driver's side brake lamp failure for ..years.

After repeatedly checking the various components/connections, esp. at N44 (but not being aware of N22 as an ingredient in all this..), I've only ever been able to get it working by banging the underside of the dash at the glovebox a few times, when the two (Brake, Stop) warnings lights appear. It can work for many, many months, and in fact had been working great for a couple of years.

Yesterday, the warning lights started blinking on again, only this time all the brake lamps failed. So I studied up here (thanks all, esp. Steve, and Jason - for the diagram) and began the whole examination process, but now including the light grey N22 control box.

Detaching and cleaning all the usual suspects made no difference. Once I got the 5 connectors off N22, opened the box up, saw no obvious problems, cleaned the connectors and reattached the wires, it all started working.

I won't say it's permanently fixed - but we're on the road, again..
 

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We're debugging a brake light failure for my son's 1993L, formerly owned by one of Steve's friends in Florida (Jacksonville?). It spent some time in the hands of a non-Alfisto, and I can't tell how much of what I'll mention is from that time. [Excised bit about N22 being bypassed, as we'd identified the wrong item as N22. Still the black unit is bypassed, but not the N22.] This car has always (IIRC, in our custody) shown fault lamps when the brake pedal is pushed. No amount of new pads, new tail lamps, ground cleaning, etc, would help that. But -- the brake lights worked. Now they don't.

It's a '93. Our other ('91/'92) 164 cars have a findable I69 relay bolted to the back of the false firewall in the advertised place. HOWEVER, this car doesn't. The stud to which the others have the relay mounted appears clean, as if there had -never- been such a relay attached. We can't find any trace of that relay in this car. Any chance (from you '93 owners out there) that the factory finally figured out not to put relays out in the elements like that? This is frustrating, but I've borne worse frustrations and will bear this one okay. We're nearing inspection time, but this is a safety issue as well as an administrative one.

All help will be appreciated. [addendum: so now that we've -really- found the N22, we can proceed with debugging. still frustrated.]
 

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1991-93 Alfa 164 brake light system troubleshooting

1991-93 brake light system troubleshooting. Start with the basics:

1. F15 fuse is 15A in main fuse box located top row full left position and HOT AT ALL TIMES.

2. The brake light switch is loacated on brake pedal and is white nylon looking not the black cruise control switch.

3.Test fuse and switch by locating white-red wire for a tow trailer wiring in trunk near rear of battery and check for 12v with meter or for light with a test lamp when pedal pushed.

4. Locate brake light relay behind false firewall (only on 91-93 12v models before facelight euro spec or 24v USA models). It is there somewhere even if not on stud mount on back of firewall. Sometimes it has fallen down way below blower motor relay wiring and under blower motor or wier motor.

5. The brake light relay socket pin 30 red wire hot at all times. Pin 86 smaller red wire for relay coil is hot when brake pedal pushed. Pin socket 85 black ground wire for relay coil, Pin socket 87 red wire once relay energized by brake pedal sends power to pin A3 in N22 ARCU under glove box.

You can jumper pin 30 if it has power to pin 87 and see if brakelights come on. If not check A3 red wire on N22 for 12v power with 30/87 jumpered or with good relay installed that clicks when brake pedal pushed.

Report your findings, including finding missing brake light relay.
 

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OK. Did it again. When debugging, do -not- assume you know what you are doing just because you have done it before or can read a procedure. This time we couldn't find the I69 relay. Lo and behold, it had -fallen- down to the bottom of the firewall recess, under the A/C housing. I had my son repeatedly actuate the brake switch, and I -heard- where it was clicking away. OK. Found that. It clicks, therefore it works, right? Maybe.

So we measured its ground integrity. OK. Measured its 12V input. OK. Measured its 12V output. OK. So we go on to the N22 box, or try. This box has a few leads listed on the brake light debug procedure. It turns out that those are not the -only- leads on the connector, just the ones involved in this brake circuit. Fooled me. It was an hour or more before I understood that I wasn't looking for a connector with exactly 6 wires. Gosh. And the item isn't even labeled N22, or even anything.

OK. So we look for the red lead from the I69 relay and measure its voltage. Hmm. 4V isn't enough. Back up to the I69 relay. Hmm. Not putting out 12V even though I -thought- I'd verified that earlier. OK. Relay clicks its little heart out, though. Let's open it up! My gosh, what a nasty, rust-ridden interior. It must have been sitting in water for a long time at the bottom of the firewall space. Pulled a spare out and Voila! Brake Lights for the son's car. Both an administrative and factual improvement.

If that relay hadn't been making its noise, I might never have found it short of opening up the firewall area. If someone else benefits in finding the I69 relay by sonic means, this writeup will have been worthwhile.

Michael
 

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Wasn't that amazin?
 

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Discussion Starter #19
I think I had the same issue finding the relay. I think Steve told me to look harder, it's down there somewhere...It was!!
 

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I had one like that on my 91S. It was buried down under the fan housing in some nasty rotted leaves from when the PO had the car many years ago. I don't remember now, but isn't there a drain there that should be kept clean?
 
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