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Don 'Mo Lurch'
Don 'Mo Lurch', VW Mechanic
Category: VW
Satisfied Customers: 20801
Experience:  Heavy Line Mech-, Mobile Electronics. Sales, Installation & Repair for 30 years. R/S, etc.
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I have a 5sp 99.5 jetta iv 2.0. I just added aux back up

Customer Question

hi, i have a 5sp 99.5 jetta iv 2.0.
I just added aux back up lights because of poor lighting in reverse. I wired 2 relays in series with tiggers tapped from passenger side reverse bulb and passenger tail light bulb, so they will only turn on while in reverse and with lights on. They work but...
My reverse lights only work when in reverse gear and lights are on when stationary with ignition on and when idling.
they turn off as soon as i try moving. As soon as i let the clutch out and rpm's change they turn off.
When i stop and depress clutch they turn back on.
I don't think adding the aux backup lights caused this, but it sure did bring it to my attention.
What do I need to check and change.
Thanks
Submitted: 1 year ago.
Category: VW
Expert:  peterpete190 replied 1 year ago.

My name is ***** ***** I am a professional here at Just Answer. I noticed that your question had not received a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

The first thing to check here is to make sure you wired in the relays properly and that you are not tied into any circuit that is drawing down to much voltage or to much ground from another circuit.When a circuit that is installed is drawing to many amps on another circuit this will cause low voltage or amperage through the factory circuit which in turn can cause various electrical issues like this here.Make sure you wired these in correctly.

If this was already checked and found to be o.k. let me know so we can continue with this here.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.Thanks Pete.

Customer: replied 1 year ago.
This is how I wired it:
14ga power and ground wires (i know the gauge is small for the length of wire run but won't be on for long periods of time)
18ga trigger wires
soldered all terminals and connectionspower is from 75x terminal from relay panel under dash
then to 15A fuse block, then to relays mounted in trunk by gas filler motor.
(i have to get wire from dealer for fuse box.)fused power wire to #30 on relay1,
#87on relay1 and #30 on relay2 are wired together,
#87on relay2 to rear lamps through existing grommet in trunk..
#85 from relay1 & relay2 are grounded to grounding terminal in trunk left side under c pillar.
aux back up lamps are grounded to bumper mounts.
relay1 #87 is wired to right back up wire
relay2 #87 is wired to right tail light wire.
I did this so I didn't need a switch. it won't work unless both relays are triggered and it does work.The aux back up lamps work with ignition in on position with gear in reverse and parking lights on.
when engine started and clutch press down and gear in reverse, it also works.
however when I actually start to reverse the car it turns off.
When I release the clutch to engage reverse gear the lights turn off. If i press the clutch down again they turn back on. It's a mystery to me.So, do I need to check relays if the lights work?
they are electrical taped side by side. should they be spaced apart?
Expert:  peterpete190 replied 1 year ago.

This is a difficult one for me to be able to answer fully here myself.I will open your question up for others here to see if someone else can assist further on this as there may be others here that may have more info on what to check or do with this issue.I hope you can get this resolved with ease.No need to reply to my last post here unless it is a last resort as it will keep your question locked to me and others will not be able to view it.If you feel you want to continue to work with me on this feel free to reply at any time but keep in mind in some cases it can be difficult to fully diagnose or help repair this without seeing your vehicle.

Thanks Pete

Customer: replied 1 year ago.
I had someone watch the lights while i reversed. they turn on as i said. they stay on until i press the accelerator. when backing out of my garage and just letting the clutch out without pressing accelerator they stay on all the way down my driveway. But when I reverse up my driveway while pressing the accelerator they go out. If i take my foot off the accelerator they turn back on.
Its not the new lamps! I took the fuse out so they do not get power and did the test again. same thing happens to stock reverse lights.
Is reverse sensor RPM sensitive? The only thing i had replaced in the last year was the cam position sensor, the car died unexpectedly while driving. Also I had the A/C overhauled, new compressor and evaporator. I think the reverse lights have been acting like this for a long time. I always have to toe/heel the brake and accelerator while backing up my driveway for extra light.
If this info doesn't helpyou diagnose my issue, refer me to a new VW Mechanic again.
Expert:  Don 'Mo Lurch' replied 1 year ago.

Please reread your connections to the Relays........
You do not show any connection to Relay PIN "86" to activate the Relay/s
SPDT Relay:
PIN 30 = Fused Voltage +
PIN 87 = Voltage + to New Back Up Lights
PIN 85 = Ground -
PIN 86 = Voltage + from Factory Back Up Lights when in Reverse

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Customer: replied 1 year ago.
It's a misprint, I typed 87 instead of 86. And they work as intended. As i wrote to pete, i tested with and without aux lights. Same thing happens.
So the problem exists with or without extra lights. What would cause the Reverse lights to go out while pressing accelerator? Is there a sensor?
Expert:  Don 'Mo Lurch' replied 1 year ago.

Your connection to the New Back Up Lights is the problem.
There is NO way that Voltage would drop or go off IF PIN 30 is connected to a Voltage + source that does NOT drop or drop out in Reverse with RPM
You need to be sure PIN 30 is constant Voltage + in Reverse & RPM up
IF NOT, then locate another source
The Relay is Activated by the Factory Back Up Lights, so if the Relay is still activated in Reverse with RPM up, then the only issue is PIN 30 Voltage +
So it will not matter what source you use for PIN 30, as the Relay will only be on in Reverse
I would never use Factory Lighting source to power a component because of the complexity of the Lighting Module & sense of AMP draw thru the Lighting Module, which connection of another source can damage the Module

.

Customer: replied 1 year ago.
I disconnected my aux backup lights by removing the fuse effectively bringing it back to stock condition. The same thing happens to the stock lights so the relays are not the issue. should i upload a video showing the lights when i back up my driveway?
Expert:  Don 'Mo Lurch' replied 1 year ago.

I never posted that the "Relays" were the issue

I understand what the Lights are doing when you increase the RPM
IF the Factory Back Up Lights were NOT doing that prior to Installation of Relays, then there was a mistake made.
The use of Relays (250ma to activate) connected to the New Back Up Lights should have had no affect on the Factory Back Up Lights & RPM, unless there was a ground or over draw of the Lighting Module

.
I disconnected my aux backup lights by removing the fuse effectively bringing it back to stock condition.

Fuse removal would not assure that there was no mistake made nor really knowing if the connections were correct.

.

IF you have checked all wires & connections & the Factory Back Up Lights are still shutting off when RPM is increased, then something has went wrong

Here is Schematic for the Back Up Lights
click attachment below

Customer: replied 1 year ago.
i removed fuse to try and isolate the issue. i wanted to see if stock lights are affected the same way without the aux backup lights, and they are. I have no clue if the factory lights acted like this before but i usually had to heel toe the brake for added lights in reverse. that's why i added aux lights for the upcoming winter.
thanks for the schematic I have the bentley service manual, what am i looking for?
Expert:  Don 'Mo Lurch' replied 1 year ago.

I just posted that to assist in being sure the right connections were made...........
In my first response I posted:
SPDT Relay:
PIN 30 = Fused Voltage +
PIN 87 = Voltage + to New Back Up Lights
PIN 85 = Ground -
PIN 86 = Voltage + from Factory Back Up Lights when in Reverse.
.

Regardless if the Factory Back Up Lights work correct or not, the New Back Up Lights should be working correctly if ALL wiring to the Relays are correct, regardless of RPM
Do they?
IF so, then you could use them & have the VW Light Circuit tested to repair the Factory Back Up Light issue or leave as connected.
There should be no RPM concern to the Factory Back Up Lights

.

IF you need more information, please ask "prior" to Rating.
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Please do the right thing and leave a rating, using the rating system, so I may be credited for this Q&A.
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NOTE: Do NOT Rate on how much TIME you waited, because I am not on 24 / 7 and I answer as soon as I see the question.
The question will still remain open for follow up questions if needed.

Customer: replied 1 year ago.
thanks for trying to help, but we have not communicated well. I tried to give you all the information I could think of. You are not helping me trouble shoot the situation and not taking in consideration what I write. It was an obvious typo with the relay numbers. I requested detailed help but only give general explanation. I expected for you to walk me through it by giving detailed instructions.I'll just bring it in to vw shop.
Expert:  Don 'Mo Lurch' replied 1 year ago.

you are not giving me accurate information & I cannot be more "blunt" in what you need to do.
I was not there when you made the connections or Install
I assumed you posted the wrong PIN numbers, but since I am not able to physically see or lay hands on the vehicle, we depend on the customer to give accurate details
I have never seen your vehicle & by your response, you have no idea if the Factory Back Up Lights functioned correctly..........
I posted 2 times to connect a Voltage + to PIN 30 of your New Back Up Lights Relays to assure constant Voltage + & NOT use what you have wired into.
This is NOT a complex job.
Relays were activated via Factory Back Up Lights
IF you have wired as I posted, then there is NO issue
There is no "walk thru"??.......you either connected as posted or you didn't.........there isn't that much wiring to this
IF you refuse to wire the way I posted, then by all means take it to someone else
My answer was to the point, & there should be no questions if you know how to complete electrical connections
I have no clue why you state I am not helping you, with 5 responses & me not able to see what you have done.........

I have over 30 years Mobile Electronics experience & know how difficult it can be to someone that has not experienced newer electronics & could have shorted something internal

Customer: replied 1 year ago.
Hi, I understand your point, it can be frustrating when the thoughts we are trying convey to each other are not clear.
But your last post is proof we are not communicating. I stated that I took my wiring out of the equation. I disconnected the fuse and trigger wires from tail light. I stated that the factory back up lights react the same way, multiple times. So it must be something else.
You keep referring me to address the 30 pin on the relay. but as i stated, I disconnected all my wiring but I left it grounded to the ground terminal G50 in trunk. and my power source is 75x terminal from the distribution panel under the dash. other than wiring directly to battery there is not a better power source.
I reconnected everything back, except I connected both pin#87's the rear taillight bulb (grey/red wire) and not to back up light bulb (black/blue). and guess what the new aux backup lights stayed on. So its not my wiring and has to be something in the factory back up light circuit. So I'm just going to replace the backup switch.