P38 (1998) pulsing lights

[Rutland_P38]

Hi, I wonder if anyone can help diagnose the following problem on a P38 1998 4.6 HSE ?

Basically the lights (and I mean all lights / electrical functions) pulse, inlcuding interior lights HVAC panel etc. This is a slow pulse, ie does not seem to be related to engine revs. It started recently after a head gasket change.

The battery charge seems good (measured across the battery gives about 14.2-14.6v), and the vehicle has no problems starting or holding charge / used as my daily vehicle both day and night and performs great.

I would guess that it would seem to be the alternator (or perhaps the recitifier ?) but I dont really want to jump in and replace it without checking other possibilities first.

Any ideas ?

Thanks.

[Pascaltissot]

It seams they forgot to clean the ground cable well or worst they just forgot to connect it check this and this might fix
all your problems .
Saludos
pascal

[Pascaltissot]

I read this info on the web it might help even more .(all data web )
DETAIL

Intermittent And Poor Connections

Most intermittent problems are caused by faulty electrical connections or wiring. A sticking relay or solenoid can also be a problem. When diagnosing intermittent problems, check the following items:

1. Poor mating of connector halves.

2. Terminals not fully seated in the connector body (terminal backed out).

3. Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material.

4. Improperly formed or damaged terminals.






All connector terminals in problem circuits should be checked carefully to ensure good contact tension (Figure 1). Use a corresponding mating terminal to check for proper tension.

5. Poor terminal to wire connection.
Examples of this are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself and corrosion in the wire to terminal contact area (Figure 1).

6. Wire insulation which is rubbed through, Causing an intermittent short as the exposed area touches other wiring or parts of the vehicle.

7. Wiring that is broken inside the insulation.

8. Corroded wiring inside the insulation.
Both the conductor and insulator must be free of any corrosive damage to ensure good conductivity.


ACTION REQUIRED

Upon customer complaint for the symptoms outlined, perform the specified repairs.

PARTS INFORMATION

No specific parts apply to these inspections and repairs. Individual connectors may be needed.

PROCEDURE

Perform the diagnostic procedures and repairs outlined in the following pages for troubleshooting and repair of poor connections.

CAUTION: 1. Use a high impedance (10 megohms or higher) digital multimeter for troubleshooting.

2. When disconnecting a connector, pull on the connector halves. Do not pull on the wires to the connector.

3. Gold-plated terminals must not be mated with tin-plated terminals.

[Rutland_P38]

Hi,

Thanks for that Pascaltissot I will have a look, they 'only' did the head gasket but they did have to take the alternator wetc. off to do this.

I will have a good look round and let you know, next week.

Thanks again.

[Rutland_P38]

Hi,

Still pulsing away !

Had a good look around the alternator and battery, but no loose / bad connections, any more ideas ?

Ohhhh BTW when looking for loose connections I DID find a water leak on small thin radiator return hose to the header tank !!!! looks like someone had caught the pipe when chaning the battery, and that was the reason for the slight loss of water (not head gasket / block etc.!!!) replaced and now all ok no loss of water, but still checking it just in case !!!

Just thoose lights, perhaps change the alternator anyway ? what do ya think ?

Thanks anyway

Chris.

[Pascaltissot]

Is there a way that someone could lend you an alternator ???it would be wiser to try this before, because I am not very sure that the problem comes from the alternator ,and it is expensive to change it for nothing , did you clean very well the fuse compartment in the engine right part, next to the water tank ?? change fuses from one socket to another ( respecting the fuse capacity and specification )and also the fuse box under the right seat . keep me informed ,I am looking in my two cars other possibilities ok . I will let you know if anything new comes up and you to O.K.
Saludos
Pascal.

[petespokerplanet]

I have the same problem I think. Mine is a very slight fading of the interior lights, and it is not related to RPM. And I have been having battery problems, so they replaced alternator and battery. The alternator checks fine and so does the battery.

[Rutland_P38]

Hi,

Just in case anyone is interested and for future reference, I have got my lights sorted at last.

It WAS the alternator, but not as expected (!!)

It was outputting too much voltage (overvolts) and this caused all manner of funny little problems, including pulsing lights etc.

replaced alternator, all OK now. Thanks for the help and advice.