99 Chevy Tahoe - The 1947 - Present Chevrolet & GMC Truck Message Board Network

brijack · 12-17-2009, 10:16 AM

First: My daytime running lights quit working. Dash shows that they are on but the lights do not illuminate.!?

Second: My fan has quit working!! It was working on high and medium sometimes. Now today it is not working and in -20 F! I think it is the resistor or something like that.!?

Can anyone give me some help???!!! Thanks!!!

DirtyLarry · 12-17-2009, 12:51 PM

Typically the loss of DRL is a failed multifunction switch (turn signal switch). The fan issue could be a resistor as you mentioned or even the fan itself.

MattA · 12-24-2009, 11:19 AM

99 Tahoe is the old body style correct? If so the DRL problem is usually the DRL diode. Its under the dash left of center. Its a small metal box with cooling fins. If you bend the tabs on the bottom of the bracket it will slide off.

Blower issues are usually the resistor. Check the connector also, sometimes they will melt the ground terminal.

Hit the motor with your hand or a hammer with power to it. If the motor is bad sometimes this will get it going again.

brijack · 12-26-2009, 07:45 PM

Thanks for the information on the fan motor!! I replaced the resistor but that didn't do the trick!!?? It must be in the fan switch or the module that it is part of????!!! If I push on the fan switch and turn to high, I can get it to work but only on high!!!?????

On the daytime running lights, do I replace this DRL that you all are talking about? Not sure if I really want them back on but was wondering if that would have anything to do with the fan/heat/defrost module.!!

MattA · 12-26-2009, 08:44 PM

The DRL and the fan are on seperate circuits and will not affect each other. Usually a blower that only works on high has a bad resistor, but it could be a switch also. Double check inside the resistor connector to make sure it didnt get hot. Hope this helps.

**truckdude239** · 12-26-2009, 10:47 PM

GM has a problem witht the control modules on teh ehater motors and sells a rewire conector to fix the problems i believe

**bwood** · 12-26-2009, 11:56 PM

On the fan issue I vote bad control head (where the fan switch is mounted). Mine is bad too on my 98 and does not turn off. And the last time it failed, about 5 years ago, it only had the two highest speeds. I don't believe you can get just the fan switch as the control head is sold as a complete assembly. If I can ever find the time, I'm going to take mine apart and see what I can do to save $180. You might also concider having this post moved to the 88-98 section as your 99 Tahoe falls into that bodystyle, and maybe it might see more responses?

12-17-2009, 10:16 AM	#1
brijack Registered User Join Date: Jan 2007 Location: Squaw Lake, MN Posts: 9	99 Chevy Tahoe First: My daytime running lights quit working. Dash shows that they are on but the lights do not illuminate.!? Second: My fan has quit working!! It was working on high and medium sometimes. Now today it is not working and in -20 F! I think it is the resistor or something like that.!? Can anyone give me some help???!!! Thanks!!!

12-17-2009, 12:51 PM	#2
DirtyLarry Windy Corner of a Dirty Street Join Date: Jun 2003 Location: Pueblo West, Colorado Posts: 2,926	Re: 99 Chevy Tahoe Typically the loss of DRL is a failed multifunction switch (turn signal switch). The fan issue could be a resistor as you mentioned or even the fan itself. __________________ Current vehicle collection: 1978 Chevrolet K10, 8.1L, NV4500, NP205 1989 Chevrolet Suburban, 8.1L, NV4500, NP241 1993 Chevrolet C1500 Sportside, TBI 7.4L, 4L60E 2001 Chevrolet K2500HD, Ext Cab, SWB, 8.1L, ZF 6 speed 2014 Chevrolet Impala LTZ 3.6L Vortec 8.1L because life is too short to tolerate underpowered vehicles Instagram

12-24-2009, 11:19 AM	#3
MattA Registered User Join Date: Jul 2003 Location: Plano Posts: 83	Re: 99 Chevy Tahoe 99 Tahoe is the old body style correct? If so the DRL problem is usually the DRL diode. Its under the dash left of center. Its a small metal box with cooling fins. If you bend the tabs on the bottom of the bracket it will slide off. Blower issues are usually the resistor. Check the connector also, sometimes they will melt the ground terminal. Hit the motor with your hand or a hammer with power to it. If the motor is bad sometimes this will get it going again.

12-26-2009, 07:45 PM	#4
brijack Registered User Join Date: Jan 2007 Location: Squaw Lake, MN Posts: 9	Re: 99 Chevy Tahoe Thanks for the information on the fan motor!! I replaced the resistor but that didn't do the trick!!?? It must be in the fan switch or the module that it is part of????!!! If I push on the fan switch and turn to high, I can get it to work but only on high!!!????? On the daytime running lights, do I replace this DRL that you all are talking about? Not sure if I really want them back on but was wondering if that would have anything to do with the fan/heat/defrost module.!!

12-26-2009, 08:44 PM	#5
MattA Registered User Join Date: Jul 2003 Location: Plano Posts: 83	Re: 99 Chevy Tahoe The DRL and the fan are on seperate circuits and will not affect each other. Usually a blower that only works on high has a bad resistor, but it could be a switch also. Double check inside the resistor connector to make sure it didnt get hot. Hope this helps.

12-26-2009, 10:47 PM	#6
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,230	Re: 99 Chevy Tahoe GM has a problem witht the control modules on teh ehater motors and sells a rewire conector to fix the problems i believe __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

12-26-2009, 11:56 PM	#7
bwood Registered User Join Date: Jan 2003 Location: Denison, Texas Posts: 1,919	Re: 99 Chevy Tahoe On the fan issue I vote bad control head (where the fan switch is mounted). Mine is bad too on my 98 and does not turn off. And the last time it failed, about 5 years ago, it only had the two highest speeds. I don't believe you can get just the fan switch as the control head is sold as a complete assembly. If I can ever find the time, I'm going to take mine apart and see what I can do to save $180. You might also concider having this post moved to the 88-98 section as your 99 Tahoe falls into that bodystyle, and maybe it might see more responses? __________________ 1998 GMC Sierra SLE 1/2 ton 2WD 305 Vortec -Gibson Stainless Cat Back Swept Side -SS Wheels 2005 Honda CRF250R 2006 Honda CRF150F Last edited by bwood; 12-26-2009 at 11:58 PM.



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