so i have been having a small problem with my truck lately. i noticed that my head lights ( as well as all other lights) are flashing at idel as well as at any RPM. i noticed that it kinda flashes to the same pulse as the motor. the motor sounds like it is revving up maybe 1-200 rpms. my first thought is the brand new alternator that the dealer put it. i put a volt meter on both batteries while the truck was running. and it was jumping from 13.4-14.8 volts... so that tells me that the alternator is doing its job. my next guess was a fuel problem causing the weird idel. i changed my fuel filter which was way over do to be changed. it still does it and its kinda making me worried. id rather not take it to the dealer. can anyone give me another idea to check to see if i can get this knocked out..??? thank you

I would check the relays, this is just a quick answer but open the underhood fuse panel and while the lights are blinking , touch the relays and see if you can feel one clicking, with the engine running you probably will not hear it but you should be able to feel it. I think there are more relays under the dash. If you find a relay that is bad , change it and see if the problem goes away, if not then that circuit must have a short and you will have to find it. I think some of your other problems are all related to the blinking , the voltage would go up and down and if it is a short cicuit, it could cause the engine to change RPM,s Charlie

ill have to check that. it might just be that because it all the sudden started doing it a few days after i put my cab clearance lights on. but i did unhook every after market powered item i put on to see if something wasn't grounded right. it still did it..

ok i went over all the relays in the engine compartment as well as the ones on the side of the drivers dash. i did not feel any clicking. do you think if i start pulling fuses and relays while the truck is running with the lights on. to see if i can get it to stop?

check the grounds. it sounds to me that the stealership might have not snugged up the alt cables or bat.

also have the bat's load checked for good measure you might have a bad or weak battery

i hope its not the batteries. they are two brand new optima's almost broke the bank buying them lol!!!

Have you checked the connection in the little red battery box under the hood where the batteries meet? Just wondering?

i have not. you mean the one on the driver side? ill look into that tomorrow!!!

check the grounds. it sounds to me that the stealership might have not snugged up the alt cables or bat.

also have the bat's load checked for good measure you might have a bad or weak battery

X2 Probably corroded or loose.

just went over all that everyone had listed today.. all grounds are attatched good. all connectors are in right. no visible wire splits...... im thinking of taking it over the hill to a little shop that does just alternators have them check that and the batteries... i am kinda hoping it is the alternator so the dealer can replace it again for free...

so i got tired of the lights flashing and burned out on trying to figure it out on my own.. i took it back to the dealer yesterday hoping it would just be the alternator and they would fix it for free.. but no.. the tech called me about noon and told me that there was a service bulleton out a few years ago on this year truck that said adding accessories to the truck messes with the alternator. he said there is a fix for it he had to replace some connector that will end up costing me over 100 bucks??.. anyone heard of this or should i just go pick up my truck tonight with out them knowing.. its parked out side i checked !!!!

If they don't fix it, I would start the truck a unplug the connector on the Alternator. If the lights stop Flickering its the Alternators Diodes going bad, Which means the diodes are letting the AC voltage pass through

Did he tell you what connector he was talking about ? He just giving you some BS. I have accessories on my truck , run a power inverter alot and jump start heavy equipment often. I have a computer in my truck, 2 phones and a printer and a back up camera and a DVDS player I installed . My lights are fine. Charlie
PS. I forgot about the 4-55watt spot lights monuted on top of my cap and the 2 -55 watt under bumper back up lights plus interior lighting for the cap.

INFORMATION
Bulletin No.: 02-06-03-008D
Date: July 21, 2008
Subject:
Low Voltage Display on IP Gauge, Lights Dim at Stop Lights, Battery (http://www.alldatapro.com/alldata/PRO~V132930621~C38623~R0~OD~N/0/101825161/104091466/104091572/104091579/34853741/34863246/34863247) Discharged, No Start, Slow Cranking, Dim Lights at Idle, Low Generator Output

Models:
1990-2009 GM Passenger Cars and Light Duty Trucks (including Saturn)
2003-2009 HUMMER H2, H3
2005-2009 Saab 9-7X

Supercede:
This bulletin is being revised to add the 2009 model year. Please discard Corporate Bulletin Number 02-06-03-008C (Section 06 - Engine).
Any vehicle may have a low voltage display (if equipped with gauges), lights that dim at stop lights, slow cranking, no start, low generator output at idle or dim lights at idle when electrical loads are heavy at idle or under slow driving or infrequent usage conditions. These characteristics may be more noticeable with customer added electrical accessories, or with a discharged battery (http://www.alldatapro.com/alldata/PRO~V132930621~C38623~R0~OD~N/0/101825161/104091466/104091572/104091579/34853741/34863246/34863247). These are normal operating characteristics of a vehicle electrical system and no repairs should be attempted unless a proven fault has been diagnosed.
During normal driving conditions, when engine speed is above 1000 RPM, the generator is designed to do two things:
^Supply the current necessary to operate the vehicle's originally equipped electrical devices (loads).
^Recharge/maintain the battery (http://www.alldatapro.com/alldata/PRO~V132930621~C38623~R0~OD~N/0/101825161/104091466/104091572/104091579/34853741/34863246/34863247)'s state of charge.

The following factors may affect generator and battery (http://www.alldatapro.com/alldata/PRO~V132930621~C38623~R0~OD~N/0/101825161/104091466/104091572/104091579/34853741/34863246/34863247) performance:
^Non-usage of the vehicle for extended periods of time. The vehicle's computers, clocks and the like will cause the battery (http://www.alldatapro.com/alldata/PRO~V132930621~C38623~R0~OD~N/0/101825161/104091466/104091572/104091579/34853741/34863246/34863247) state of charge to drop (For example; 30 days in a parking lot and the vehicle may not start because of a dead battery or a vehicle which is driven only a short distance once a week may end up with a discharged battery to the point where the vehicle may not start). This would be considered abnormal usage of the vehicle and the normally expected result for the vehicle battery, generator and electrical systems.

http://www.alldatapro.com/alldata/PRO~V132930621~C38623~R0~OB0~P3R0H~N/0/101825161/104091466/104091572/104091579/34853741/34850750/42063452/139128170/138433932/138510151
^At idle, vehicle electrical loads may exceed the low speed current (amperage) output of the generator and when this happens the shortfall comes from the battery (http://www.alldatapro.com/alldata/PRO~V132930621~C38623~R0~OD~N/0/101825161/104091466/104091572/104091579/34853741/34863246/34863247). This will result in a drop in the electrical system voltage as the battery delivers the additional electrical current to meet the demand. This is equivalent to the brown outs experienced by homes and businesses when the electrical demand is more than the supply. See Figure 1.
^Extended periods of engine idling, with high electrical loads, may result in a discharged battery (http://www.alldatapro.com/alldata/PRO~V132930621~C38623~R0~OD~N/0/101825161/104091466/104091572/104091579/34853741/34863246/34863247). Attempting to recharge a battery by letting the engine run at idle may not be beneficial unless all electrical loads are turned "OFF".
^Increased internal generator temperatures from extended idling can also contribute to lower electrical system voltage. As the generator's internal temperature rises, the generator's output capability is reduced due to increased electrical resistance.

http://www.alldatapro.com/alldata/PRO~V132930621~C38623~R0~OB0~P4R0H~N/0/101825161/104091466/104091572/104091579/34853741/34850750/42063452/139128170/138433932/138510150
Some typical examples of electrical loads are shown above.
Depending on the vehicle application, generator current (amperage) output at engine idle speeds of 600-700 RPM can be as low as 35 percent of the full rated output. With enough electrical loads "ON", it is easy to exceed the generator current (amperage) output when the engine is at an idle of 600-700 RPM. This is a normal condition. The battery (http://www.alldatapro.com/alldata/PRO~V132930621~C38623~R0~OD~N/0/101825161/104091466/104091572/104091579/34853741/34863246/34863247) supplements for short periods of time. Items that affect the vehicle's electrical system current and voltage at idle are the number of electrical loads being used, including add-on accessories, and extended idle times. When the vehicle speed is above approximately 24 km/h (15 mph), the engine/generator RPM is high enough and the generator current (amperage) output is sufficient to supply the current (amperage) requirements of the vehicle as originally equipped and recharge the battery.
Dimming lights at idle may be considered normal for two reasons:
1.As the engine/generator speed changes, so will the current (amperage) output of the generator. As a vehicle slows, engine/generator RPM slows and the current (amperage) output of the generator may not be sufficient to supply the loads, the vehicle system voltage will drop and the lights will dim. Dimming of the lights is an indication that current is being pulled from the battery (http://www.alldatapro.com/alldata/PRO~V132930621~C38623~R0~OD~N/0/101825161/104091466/104091572/104091579/34853741/34863246/34863247). If the battery is in a low state-of-charge (discharged condition), the driver will notice a more pronounced dimming than a vehicle with a fully charged battery.
2.When high current loads (blower, rear defogger, headlamps, cooling fan, heated seats, power seats, electric "AIR" pump, or power windows) are operating or cycled "ON", the generator's voltage regulator (http://www.alldatapro.com/alldata/PRO~V132930621~C38623~R0~OD~N/0/101825161/104091466/104091572/104091579/34853741/34863246/34863337/34863603) can delay the rise in output. This effect, usually at lower engine speeds, can take up to ten seconds to ramp up the generator output. This is done to avoid loading the engine severely. To increase current (amperage) output, additional torque is consumed by the generator. The engine computer (ECM/PCM) will ramp up engine/generator speed in small steps so engine speed variations are not noticeable to the driver.
For diagnosis of the battery (http://www.alldatapro.com/alldata/PRO~V132930621~C38623~R0~OD~N/0/101825161/104091466/104091572/104091579/34853741/34863246/34863247) and/or the generator, refer to the appropriate Service Information (SI) or Corporate Bulletin Number 05-06-03-002C.

http://www.alldatapro.com/alldata/PRO~V132930621~C38623~R0~OB0~P4R0H~N/0/101825161/104091466/104091572/104091579/34853741/34850750/42063452/139128170/138433932/83196614

part number 318 "wire" $0.45 x8 $3.60
" "12048074 "terminal 8.965" $2.18
" "12186568 "connector 2.313" $6.83

total parts $12.61

total labor $159.90 :eek:-:t

this is why i need to find a "guy" . Although would would the little guy have know about the service bulletin. and or known to look for this plug?