Electrical system surges at idle/low rpm

[HotRod SVT]

This is on my 98 E0 SVT, 3.0L swapped. I bought the car summer of last year with a bunch of issues and one was a bad alternator. So I replaced it with a stock replacement Remy Gold brand new not a refurb 130 amp with a lifetime warranty from rockauto. Well I’ve done a ton of work on this car since I bought it and have only driven it a handful of times but I’m having an issue with the lights surging and I can’t figure out what’s wrong.

It does it at idle and low rpm but above around 2500-3K it seems to go away or it’s flashing so fast it appears to go away, also if the lights are off at idle and you turn them on the surfing will go away for a few seconds but then return.

Another issue I’ve had since I moved from Tx to MI is the ABS light is on and the Blower Motor quit working both of which wasn’t the case as I had recently recharged the a/c system before moving and the blower was working fine. I do currently have the radio removed and unplugged but I don’t see that being connected to this issue. I’ve checked all the fuses under the dash and hood and all are good.

Looking for opinions and ideas. Thanks

 

[Chris@CTA]

Make that times 2. I wish I had a definitive answer, but my SVT is experiencing a similar issue. The one thing I find is that it might be the battery. I see that my SVT, the surging isn't as bad once the battery has a good charge, but when the car has been sitting for a few days or weeks, and then started up, the surging is pretty bad. I do have a trickle charger on a timer to top up the battery on a regular basis. If you have a multimeter to test the battery voltage, or better yet, a volt gauge in the car, check the voltages from engine off to when engine running.

Just a thought.

 

[BrApple]

Need to get a volt meter on the battery and see what the voltage is doing. surging lights is normally a sign of overcharging, iirc. Often even "new" alternators have issues. Its pretty difficult to get a good alternator for the Contour.

As for the blower motor and abs light, they are on the same 60 amp (iirc) fuse in the engine bay fuse panel. Search around, but I forget what causes this issue, but it normally happens when the abs engages. It will take the fuse out. Chances are the wiring under the fuse box is bad.

 

[amc49]

Some say this mod based on the TSB has worked...............

http://www.contour.org/ubbthreads/sh...fpart=all&vc=1

TSB link here in first post......says Cougar but cars are the same.

http://contour.org/ceg-vb/forum/gene...nterior-lights

Look at the heater blower motor power supply wire right as it exits the interior fusebox, they commonly melt there, the connection to the box overheats as it is too small. They all in the junkyards will be damaged close to the same way. A big red or green wire IIRC.

 

[HotRod SVT]

Ok here’s an update, I fixed the ABS and Blower
Motor issue by replacing the 60amp fuse in the under hood fuse box, It looked ok to me but everything else checked out so I replaced it and it fixed both issues.

As for the surging issue, I put my DMM on the battery and I’m getting a solid 14.3-14.5 volts at the battery at idle, so that seems normal to me.

Another thing I noticed the other day is the positive battery cable gets prettt hot when it’s running and it has the typical cracked insulation and has some slight corrosion but not to bad. I tried to find a new one but was only able to find universal replacement cables. Anyone know if the stock OEM stuff is still available? I was thinking about replacing both cables as I think they are way past there prime.

 

[amc49]

Ford and their crap too small battery cables...............they should be NLA by now but you might find a set in NOS stock somewhere. Focus have a much worse problem melting and I make my own up and much bigger cables that have lasted for many years.

The surging can be from worn brushes in the alt or a corroded output fitting and in general resistance anywhere else.

You may have 'fixed' the blower issue but look very close, these cars over time develop a melting issue with the blower supply wires that come out of the INSIDE cockpit fusebox, you have to yank the box and flip it over to find the melting. VERY common. Typical Ford again, too small a gauge wire for the current running in it longterm, then it slowly melts so they can give the CEO a money saving bonus.