Indicator flashing speed

[chris-p-duck]

Hi all,

I am looking for a bit of help if possible please. When using my 2004 C5 yesterday the passenger side indicators suddenly started flashing fast. I assumed it was a failed bulb, which annoyed me as I fitted a new bulb in the right rear about a month ago. However when I stopped and checked all the bulbs were working. The left side all work fine, the hazards work at the right speed. It's just the right side which flashes fast. I assumed it was going to be an earth problem but from what I can tell the rear lights are all linked to a common earth and the fronts are on a different earth - so if it was a rear earth issue then wouldn't the test of the rest lights be misbehaving (which they are not)? So I don't understand why the right side both front and rear would misbehave. Has anyone else had this issue or any advice as to what it might be please??
Any help will be gratefully received
Thanks

Chris

 

[teamzr1]

Have you also checked the right front lights ?​

Turn Signal Lamps​

When the ignition switch is moved to the ON or START position, battery voltage is applied to the ELEC flasher from the HAZ T/SG MiniFuse(R) #15 through CKT 1739. This battery voltage is then applied from the ELEC flasher to the turn signal switch through CKT 16.

During a right or left turn signal command, battery voltage is supplied from the turn signal switch to the instrument panel electrical center and the BCM using CKT 15 for the front RH turn signal or CKT 14 for the front LH turn signal. Within the instrument panel electrical center there are two micro relays (DRL R Micro Relay #38 and DRL L Micro Relay #40) which are used to determine whether the front turn signals or the front Daytime Running Lamps (DRL) are in operation.

During normal driving, the BCM will ground CKT 1914 and CKT 1915 which will activate the two DRL relays and illuminate the front DRL lamps. During a turn signal request, the BCM will remove the grounds from CKT 1914 and CKT 1915 which then allows battery voltage to pass through the DRL Micro Relays and illuminate the front RH turn lamp through CKT 1315 or the front LH turn lamp through CKT 1314.

The rear turn signal lamps are directly controlled by the turn signal switch unlike the front turn signal lamps. During a right or left turn signal command, battery voltage is applied to the rear RH [1][2]turn signal lamp through CKT 19 or the rear LH turn signal lamp through CKT 18. All turn signal lamps are grounded through CKT 150. Domestic/Canadian vehicles ground the front lamps by CKT 150 through Splice Pack #102 to G102.
Export vehicles will ground the front lamps by CKT 150 through Splice Packs #100 and #101 to G102 or G101. All vehicles will ground the rear turn signal lamps by CKT 150 through Splice Packs #402 and #400 to G401.

 

[teamzr1]

This C5 setup with USA lighting or Export ?

 

[chris-p-duck]

Wow there is a lot of info there. Since I am not an electrical engineer the key question is - what does all that actually mean? How do I take this info and use it to allow me to trace the issue? None of it seems to refer to what is controlling the speed of the flashing. The fact that the front and rear and controlled separately there must be common point between the two sets of bulbs and only for the right hand side?? Is that common point the DRL micro relay?

Thanks

Chris

 

[chris-p-duck]

The car is a US spec car but has been half updated to export spec. It's not a full export spec and was originally sold into the US
Chris

 

[teamzr1]

The car is a US spec car but has been half updated to export spec. It's not a full export spec and was originally sold into the US
Chris

You sure the bulbs you change are the correct ones ?
Using the wrong type or mix types would cause fast flashing

That could make it harder to trace the problem as not being stock
If you turn the hazard switch on, does all the lights flash correctly
and again make sure all lights on right side are working the same way or front right turn signal works correctly

 

[chris-p-duck]

So I swapped the new bulb into the left rear holder and the problem didn't change so I am working on the basis that it's not the bulb. When the hazards are used they all flash at the right speed. The only thing I hadn't checked were the other front lamps (pop ups). Just been out to the garage to check and they are working fine. Irritatingly having put the headlights on, checked then and turned then of, the right indicators are now working fine . Which on one level of great on another, there is clearly something wrong which is still wrong. Thanks for the help though. If there is anything else I can check then please shout as I can see this happening again....

Thanks

Chris

 

[Oneball]

The flasher unit works by passing current through a bimetallic strip. As it heats up it bends and breaks contact, as it cools it bends the other way and contact is made again. The frequency this happens at is affected by the current through it. A change in the resistance of the circuit such as a blown bulb or poor contact will affect the frequency. Your lights could still flash but corrosion of the bulb or holder the wrong bulb could affect the frequency

 

[C5Steve]

Have you checked all your bulbs, not just indicators? Really weird it's not a bulb out. If every single bulb is fine, then work your way back. Could be the stalk itself (multifunction switch I think it's technically called) as it's just the one side. Could be the flasher unit but it's usually both sides if it's that.