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BRD

1990 Buick Reatta “Cycling” Parasitic Draw Challenge

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Posted (edited)

Thanks for the information Ronnie and 2seater.  Here comes another novel…  Have some more information based on latest round of tests and additional photos.  2seater, the date on my door is May 1990 and I have a relatively high VIN (i.e. a lot closer to 8000 than 0000).  So this, coupled with fuse and relay information makes me think it’s a “late year” model.  I have had this “lights on” problem on my digital display on three different IPCs over last 10 years – so I don’t think they are the cause.  I did change out my headlight switch assembly around 10 years ago.  It is possible that this is when the “Lights On” fault on my digital display occurred but I cannot remember.

 

Recharged the battery and performed the following today:

 

1.  Disconnected “orange” set of wires connected to Headlight Door Module.  Turned key to “on” position without starting the engine.  Both the “orange square” indicator light on the headlight switch and the “Lights On” remained on.   Turned key back to off position.

2.  Disconnected “green” set of wires connected to Headlight Door Module.  Turned key to “on” position without starting the engine.  Both the “orange square” indicator light on the headlight switch and the “Lights On” remained on.  Turned key back to off position.

3.  Disconnected negative battery cable and connected multimeter to check amps.  Had an initial reading of 3.6 amps for ~ 15-30 seconds.  It then dropped down to 0.06 amps and held steady there.

4.  Disconnected multimeter and connected again.  Amperage started and held steady at exactly 0.06 amps for several minutes.

5.  Removed dash panel and disconnected both the red and green plastic connectors to the headlight switch assembly.  Then turned key to “on” position without starting engine and the “Lights On” light on the digital display was gone (I think) because then screen quickly went to “Error 00” and nothing more.

7.  When I connected only the red side (with five wires) the small orange light on the assembly would come on.  But the “Lights On” would not illuminate on the digital display.

8.  When I connected only the green side (with the 12 wires) the small orange light would not illuminate and the “Lights On” would also not illuminate on the digital display.

9.  When I connected both the red and green connectors the “Lights On” would also display on the digital instrument panel.  (But this happened quickly before the “error” display)

10. After I tried replicating this with several tests the digital display would only show the “00 Error” screen and nothing about the lights, as a normal "full" display would show.

11.  Looks like the fourth “burned pin” on the green connector is predominately black in color with a thin purple strip.  You can also see how it is thinner at the base than the other wires.

12.  Visually looked in the engine compartment for similar wiring.  Neither the “green” nor the “orange” wire bundles going into the Headlight Door Module have a similar black/purple wire.  I did find a similar black/purple wire (but much larger) going into the Engine Relay Center Box and also in the vicinity of the right headlight (photos attached).

13.  I am confident that the only time the small orange square illuminates is when I attach the red connector (with the five wires) to the headlight switch assembly (even without inserting the key).

14.  I am not 100% sure but it seems that the only time the “Lights On” illuminated on the digital display was when both the green and red connections were inserted into the headlight switch assembly.

15.  I could not get the dash to illuminate fully (only the “error screen”) when I tried turning key on subsequent tests with both the green and red connectors attached.  (photo below)

 

This leaves me with a few immediate questions:

 

1.  Is it possible to run power to the corresponding “fourth pin” on the headlight switch assembly via a jumper to see if that affects the “Lights On”?  Or to somehow test/trace the black & purple wire coming out of it?

 

2.  Are the wires included in the red connector supposed to be “hot” always?  Isn’t there always supposed to be power to headlight switch by design – even if key is not in ignition?

 

3.  Is it possible that the headlight relay modification (zip tied) in my late? model Reatta causes this orange light to always be on?  (Or maybe if I can confirm if any other 1990 late year model owners also have that “orange square” light on all the time?)

 

4.  What would you recommend I try next based on this information?  I'm still not 100% convinced that the 3 amp draw has anything to do with the headlights/headlight doors - although it certainly seemed that way two days ago and I still think/agree it is probaby the case.  But I do not understand why I got that initial 3.6 amp reading today when connecting the multimeter without the "green" and "orange" bundles connected to the HDM.  2seater, it seemed that you also had the initial 3 amp reading on your multimeter as well before it drops down to something more normal.

 

Greatly appreciate your thoughts!

 

BRD

    

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Edited by BRD

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Something about the number 4 spot in the connector isn't right. Not sure what is going on. Looks like the small part on the end is either been really hot exposing the copper causing it to look black from heat or melted insulation. What is so odd about that is that the way the insulation stops is so uniform and from there on back it doesn't appear to have been hot.  When I blow up the photo and look closely at where the wire goes into the terminal it looks like there is solder on there. Since you said you have owned this car for years that probably isn't the case. Have you ever had anyone work on the headlights before? At any rate that terminal 4 in the connector needs to be fixed from what I can tell by looking at all your photos.

 

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2 hours ago, BRD said:

1.  Is it possible to run power to the corresponding “fourth pin” on the headlight switch assembly via a jumper to see if that affects the “Lights On”?  Or to somehow test/trace the black & purple wire coming out of it?

I can't find a wire with that color in my FSM for my '88. It must be unique to later models. Without knowing what that wire does I would be afraid of connecting a jumper directly to it with 12 volts. I would rather connect the headlight switch to the connector and the back probe the wire connections with a meter [while pushing the buttons to turn on the lights] to do the tracing.  If you can find that black/purple [I actually think it is a pink stripe] in your FSM that would be the best way to trace it.

 

2.  Are the wires included in the red connector supposed to be “hot” always?  Isn’t there always supposed to be power to headlight switch by design – even if key is not in ignition?

I believe orange wires are almost always hot all the time but I not certain of that.

 

3.  Is it possible that the headlight relay modification (zip tied) in my late? model Reatta causes this orange light to always be on?  (Or maybe if I can confirm if any other 1990 late year model owners also have that “orange square” light on all the time?)

I doubt it.

 

4.  What would you recommend I try next based on this information?  I'm still not 100% convinced that the 3 amp draw has anything to do with the headlights/headlight doors - although it certainly seemed that way two days ago and I still think/agree it is probaby the case.  But I do not understand why I got that initial 3.6 amp reading today when connecting the multimeter without the "green" and "orange" bundles connected to the HDM.  2seater, it seemed that you also had the initial 3 amp reading on your multimeter as well before it drops down to something more normal.

I think the next step is to figure out what the wire does that goes to. Was there a wire with that color on the HDM?  It would be best if you can find it in your FSM but if you can't you will have to trace it someway.  When you find were it goes you may find a defective relay or something that caused it to overheat. .

 

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I don’t have much to add at this point except in my experience, black wires or variations such as with a stripe are some form of ground. There is a connection to ground indicated on the far right side of the switch schematic listed as ground for the indicator light in the switch. No wire size or color is indicated so guess is the ground is internal to the switch?

Excellent photos by the way. Something I am lousy at. 
Have you tried removing that discolored connector? I don’t know if it is push or pull type of install 🤨

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Posted (edited)

2seater and Ronnie:  Thanks for the recommendations and photo comment - I use a five-year-old smaller iPhone camera that allows me to get into the tight car spaces for close-ups.  Answering your questions: No "black/pink" wires going into the “orange” and “green” sets of Headlight Door Module connectors.  Have had mechanics over the years replace/overhaul the headlight motors but I am not aware of anyone touching the Headlight Light Switch Assembly.  It’s possible that a mechanic put in the new switch assembly 10 years ago but equally possible that I did it.  Can’t remember.  Have not yet tried removing the burned connector but that might be one of my next steps. 

 

Have some additional updates:

 

1.  Found two references to a black/pink wire in the 1990 Service Manual.  Have included a few pictures below mentioning this color wire.  (My working assumption is that the first color listed is the predominant color and the second listed is the smaller “stripe.”  Please let me know if this is not the case).  Saying this because there is also a pink/black wire listed in the light section.  Don’t want to confuse the two.  For clarity, my understanding is that the “black/pink” wire is the one that goes into the burnt green plastic terminal.

 

2.  Found a black/pink wire in the front of the car going into the Outside Air Temperature Sensor.  I would normally think this has nothing to do with “Headlights” but it is actually referenced in the “Headlights” section of my 1990 Service Manual and mentions that it is part of the same wire bundle.

 

3.  Attached photos of the black/pink wire connecting to the Outside Air Temperature Sensor and the green connector going to the Headlight Switch Assembly.  They look identical color/gauge to me.  The Outside Air Temperature Sensor wire might be slightly lighter in color in the photos (i.e. gray/pink) but in person it looks almost identical.

 

4.  Found a page in the 1990 Service Manual addressing Battery “Component Parasitic Loads.”  In the chart it mentions that BCM draws are typically 3.6 amps – exactly the draw I encounter(d).  Would this potential “headlight-related” short have anything to do with BCM draws?  Maybe this is obvious but I do not understand how components are grouped and added for aggregate draws.

 

5.  Put blue “dots” by the relevant text in the service manual photos.

 

Follow-up Questions:

 

1.  Is there “only one” black/pink wire in the entire car?  This is probably a simple question but I do not know if cars usually have unique colored wires for easier maintenance and troubleshooting.

 

2.  If multiple black/pink smaller-gauge wires exist, do they splice to form a larger-gauge black/pink wire?  I ask this because I can see two instances of a larger-gauge wire black/pink wire running into the engine center relay (photo included).  Does this somehow connect to other smaller-gauge black/pink wires in the car?  (Is this an electrical wiring convention/protocol?)

 

3.  If I trace the black/pink wire from the green Headlight Switch Assembly connector, would that usually go under the dash and then down to the fuse box?  Or out a wire-run and directly into the engine compartment?  (I don’t know how to find this wire as it disappears into a hole with all the other wires about five inches from the Headlight Switch Assembly).

 

4.  Can I apply a current to the black/pink wire at the green plastic connector and then see if I get a similar reading at the Outside Air Temperature Sensor "black/pink" wire (or vice-versa)?  Is this too risky?  Is there another way to test this?

 

Greatly appreciate your insight and continued assistance!


BRD

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Edited by BRD

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18 hours ago, 2seater said:

I don’t have much to add at this point except in my experience, black wires or variations such as with a stripe are some form of ground.

I think 2seater is right. What he said got me to thinking so I started looking for a ground wire with the color code black/pink and I found it. It appears to be a dedicated ground of some sort. It goes to a lot of the components in the HVAC system according to the FSM (see photo). That would account for the black/pink wire going to the outside temp sensor. But, it also says it goes to a headlight switch with a twilight sentinel. Did the '90 Reattas have a twilight sentinel?

 

I also found a place in the FSM that it show the black/pink wire goes to the Courtesy Lights which is built into the headlight switch. That would account for the black/pink wire going to the headlight switch. And it also goes to the theft deterrent system. Maybe anything that requires a ground to the BCM is that color?

 

All the black/pink wires come together with Splice S215 located in the wiring harness under the BCM. But they don't go to a chassis ground. They appear to be grounded at the BCM which has a dedicated ground near the battery.

 

What all this means I honestly don't know. I don't know why a ground wire that is used to signal the BCM to turn on the Courtesy lights would have enough amperage going through it to burn the terminal in the headlight switch connector like it did. I wish I had more to offer in troubleshooting the problem. All I know that you can do is fix what you know is bad first and go from there. Maybe looking up page A8-68-1 in the FSM will help you.

 

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It is a puzzler? Strange that one ground out of many would show a symptom like that unless it has been short circuited in some fashion. Much of the switching seems to be making and breaking a ground connection, just like fuel injectors, constant 12v but a switched ground to make operate. As pointed out, it is a strange looking damaged area with what appears to be heat shrinkage for a short distance on the wire. If the terminal removal doesn't work, a quick and dirty way is to clip that wire in a way it could be repaired again, but then a meter could be used to see if there is a constant draw on that wire. Is it possible the BCM is the troublemaker?

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Thanks for the response and thoughts Ronnie and 2seater.  My 1990 Reatta does not have a Twilight Sentinel.  Could be something with the BCM, as you mentioned 2seater.  Ronnie, I will look at the FSM page you referenced. 

 

It is also possible (but highly  unlikely) that the green burned out terminal was actually damaged during my first Headlight Switch Assembly "era."  Then another wire was soldered in its place to actually fix what was previously broken via the initial light switch assembly (or maybe a faulty BCM?).  Maybe that black/pink wire is actually working exactly as it should right now and we are only viewing damage from the past?

 

The red connector (with the five wires) is 100% the connector that is causing the constant small orange square to illuminate.  Maybe something else is causing the “Lights On” to stay lit on the digital display (e.g. maybe the replacement headlight switch assembly was always faulty – or a bad signal from the BCM?)  Maybe something else is actually causing the cycling 3.6 amp draw? (Although there is no doubt that when I initially disconnected the HDM connectors that problem seemed to stop)

 

There are unfortunately a number of other electrical items on my car that also do not work properly any more (e.g. alarm system for past 20 years, chimes do not sound any more, parking lights have at times not worked properly, three speakers blown out, tail lights sometimes did not illuminate when turning on headlights unless I was breaking, right headlight door is still problematic, door locks stick, etc.)

 

All kinds of electrical problems over the years that I have dealt with – but not always been able to keep up with.  Still not all resolved.  Trying to take advantage of having access to basic tools and an indoor place to work on my car right now to fix as much as possible.  For many years dreamed of being able to just rewire the whole car : )

 

I will keep testing and investigating and let you know if I make a discovery.

 

Thanks again for your exceptional insight and time!

 

BRD

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Posted (edited)

That is a lot to take in and deal with and I don't have any great insight or flash of inspiration. I suspect some of the above issues are related, as I had mentioned before about the under seat splices curing door locks, rear turn signal, trunk remote, drivers door courtesy lights and other things. When they cease to function a little at a time sometimes it escapes notice. I think Ronnie even mentioned the ground wire for the alarm is in the same bunch as the indicator light?

 

Incidentally, it took 48 hours for my battery voltage to drop one tenth of a volt, 12.39v-12.29v. I have no twilight sentinel either and the indicator lights in the switch or the ipc are not illuminated unless the headlights are on.

 

Both the parking light and headlight indicator lights in the switch illuminate at the same time since parking lights always engage with headlights, and it does not matter if the key is on or off, hot all the time. In other words, the headlight indicator in the switch never illuminates by itself. The parking light indicator will illuminate alone if only the parking light button is pushed, again it does not matter if key on or off. The 'LIGHTS ON" indicator on the IPC only illuminates when the headlights are on and the ignition is on.

 

I am on my third headlight switch, and as mine is early production, the load from my uprated headlights destroyed the switch, but I was too unaware to realize what was happening. As mine is summer only, the long hours of daylight and no headlight usage probably saved the switch for years before it actually failed and only occurred after I was working a third shift job during the '08 recession and did more night driving. Previous posts detail the odd goings on as the second switch started to fail and only the addition of relays cured the switch issue and a third switch from Daves89 were all problems resolved. Since you have the headlight load removed from the switch, I wouldn't think load would be the cause of the discolored and apparently overheated connection, especially an apparent ground, unless, something was seeking a ground and chose that one??

 

It would be nice if you could try a known good tested headlight switch and possibly a headlight door module, but I have neither. They tend to get recycled, particularly the headlight switch which is either rebuilt or as a parts donor.

Edited by 2seater

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I have ignored a problem with my 'vert for at least 3 years until it manifested into a poor running condition. I did all the usual things to fix what I thought what surely had to be either a fuel or ignition system issue, so I started in by swapping out the ignition module/coil pack, MAF sensor, cleaned the Idle Air Control, verified the spark plug wires were at the correct cylinders to the right terminals at the coil, and replaced the oxygen sensor. I also checked fuel pressure and checked the fuel pump regulator and did a fuel pressure test. Everything tested out fine. Replacing the oxygen sensor helped [it looked original] but it still ran rough at certain RPMs which then made me think that it could be the fuel injectors.  

This was not the case. It turned out to be a bad front rubber brake lines. The drivers side was completely closed off and was sapping so much engine power the car didn't run right and because the caliper couldn't release the car would vibrate.

 Swapped out hoses, rotors and pads and everything is great. 

 How does this relate to you? Your story is/was similar to mine.

 You have two of the best guys on this forum trying to help you and you are continuing to bring things to the table. You finally confessed that you have some issues that you had been ignoring and what finally brought this all to a head was the fast drain on your battery.

 These guys have been very polite and have told you nicely what needs to be done first. Replace that harness connection and then roll back the carpet and check the connections under the seats ]drivers and passenger]. By your own admission you stated that the car has spent a lot of time outdoors. We "old timers" know that outside cars typically have connection issues on the wires under the carpet.

 Start there, do your repairs and report back your progress.

 

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Well said Dave!!

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